Apple Replant Disease Theory versus practice, [600513]

Apple Replant Disease – Theory versus practice,
an overview of known controlling methods

By H. Meints & A. Toma
Summary
In the past decades, several researchers focused their attention on identifying the causes of Apple Replant Disease,
along with finding new strategies to prevent and control this important threat to fruit production. From leaving the land
fallow, us ing rotation and control crops to soil fumigation and organic amendments, all has been considered over time.
Nowadays, there is a visible tendency on using environmental friendly solutions, along with an increase in banning
regulation regarding the chemic al products used in EU agriculture sector. Therefore, solutions such as Brassica seed
meal soil amendments developed by Mark Mazzola, or Herbie invented by Thatchtec in The Netherlands are the proof
that alternatives exist and can be efficient. Field trial s have resulted in an almost 100% pathogen suppression and
significant yield increase. However, in the case of Herbie and particularly in the trials conducted at Fleuren Tree Nursery
in Baarlo, experiments are pushed to their extremes trying to monitories the method’s efficiency and limitations,
regarding time frames, larger range of temperature and dosage. What differentiate this later trial from the ones
conducted by Mark Mazzola in the US, is that at Fleuren, testing lots are bigger. So far, the results obtained give a
positive trend and special attention should be paid not only to the unpredictable weather conditions and temperature
from the last period (that are obviously different from the usual values) that can affect the trials, but also try to obser ve
and monitor the soil biodiversity along the tests, complementary to the plant behavior.

Apple Replant Disease – Theory versus practice, an overview of known controlling methods
H. Meints & A. Toma
Contents
1. Background of apple replant disease (ARD) ………………………….. ………………………….. ……………………. 2
2. Control methods applied for ARD ………………………….. ………………………….. ………………………….. ……… 2
2.2 Swapping the soil ………………………….. ………………………….. ………………………….. ………………………….. 2
2.3 Using compost and compost tea ………………………….. ………………………….. ………………………….. …….. 2
2.4 Using resistant strains ………………………….. ………………………….. ………………………….. ……………………. 3
2.5 Testing the soil ………………………….. ………………………….. ………………………….. ………………………….. …. 3
2.6 Removing old plant matter ………………………….. ………………………….. ………………………….. …………….. 4
2.7 Growing ‘Break Crops’ ………………………….. ………………………….. ………………………….. …………………… 4
2.8 Fumigating the soil ………………………….. ………………………….. ………………………….. ………………………… 4
2.9 Alternative methods on fighting ARD ………………………….. ………………………….. ………………………….. . 4
2.10 Anaerobic Soil Disinfestation ………………………….. ………………………….. ………………………….. ………… 4
3. Experiments and their outcomes ………………………….. ………………………….. ………………………….. ………. 5
3.1 A closer look o ver microbial community development ………………………….. ………………………….. …… 7
3.2 Wheat – the chief mediator ………………………….. ………………………….. ………………………….. …………….. 8
3.2 Brassica seed meal amendments as alternative to soil fumigation ………………………….. ……………….. 8
3.3 Herbie – an efficient fighter against soil borne pathogens ………………………….. ………………………….. . 9
4. Conclusion and recommendations ………………………….. ………………………….. ………………………….. ……… 12
5 Field trials photos ………………………….. ………………………….. ………………………….. ………………………….. 13
6. Annex 1 ………………………….. ………………………….. ………………………….. ………………………….. ………………. 16
7.References ………………………….. ………………………….. ………………………….. ………………………….. …………… 22

Apple Replant Disease – Theory versus practice, an overview of known controlling methods
H. Meints & A. Toma

“Innovation is not just technology, but is rather a comprehensive vision of w hat the future
should look like and which requires changes in many ambits. Innovation is driven by people’s
needs, ambitions and dreams, and requires that people at different positions in society change the way
they work and live.” ( Klerkx et al, 2012)

1. Background of apple replant disease (ARD)

Replant disease is a debilitating soil problem affecting most orchards when they are replanted.
Symptoms normally affect the entire orchard and include slow, uneven growth and poor tree
performance. Due to the gener al nature of replant disease, it is easy to be unaware that it is present, or
to blame the rootstock or nursery for poor tree performance. Replant disease affects most fruit crops
including both Pome and Stone fruit (Brown,2013). During the life of an orch ard, soil -borne pathogens
belonging to the genera Rhizoctonia , Pythium , Phytophthora, Cylindrocarpon and Pratylenchus become
prevalent in the tree root zone, but they generally do not appreciably affect the health or productivity of
mature trees (Mazzola, 1998; Mazzola, 1999) . To this date, previous studies categorized replant disease
as having two forms – specific and non -specific. It is assumed that specific apple replant disease only
affects apples when they are planted after apples, while non -specific r eplant disease affects apples that
are replacing other fruit crops, such as stone fruit or vice versa (Brown,2013). The severity of replant
effects can vary from site to site (Hoestra, 1968; Mazzola, 1998). The symptoms mentioned above
include reduction in tree vigor and yield (Traquiar, 1984), and the fact that affected trees start bearing
fruit 2 –3 years later than unaffected trees. According to Mazzola (2004;2009;2015), in apple replant
disease, an important aspect to be taken into account is the microo rganisms variety built -up in the root
zone of the trees , while applying prevention and control strategies .

2. Control methods applied for ARD

When it comes to prevention methods and treatments of ARD, opinions vary, as it is a complex disease
involving di fferent causal factors. However, we will briefly list the most common measures found in the
literature and further discuss some of them more in depth in the latter part of the article.

2.2 Swapping the s oil

When is needed to replant apple trees in the sa me location – or if planting in a new location isn’t viable
– then soil replacement can be an effective method for smaller sites. It’s important to ensure that high
quality soil will be used and moreover, it doesn’t come from any fruit tree planting source . Specialists
recommend that the replacing soil should be spread on an area larger than the tree’s roots coverage,
while any old soil will be disposed.

2.3 Using compost and compost tea

St. Martin and Brathwaite (2012 ), define composting as “the controll ed, microbial aerobic
decomposition and stabilization of organic substrates, under conditions that allow the generation of

Apple Replant Disease – Theory versus practice, an overview of known controlling methods
H. Meints & A. Toma
high temperatures by thermophilic microbes, to obtain an end product that is stable and free of
pathogens and viable weed seeds and c an be used in plant culture . The end product, which is a solid
particulate extracted during the maturation and curing phase, is termed compost (Litterick and Wood
2009) ”. Further, compost tea can be referred as “filtered products of compost brewed in water (Litterick
et al. 2004) and brewing, a steeping process of compost in any solvent (usually water), which lasts for
more than one hour “(NOSB 2004).
As many previous studies show, soils amended with compost can partly or wholly suppress soil borne
phytopat hogens and plant diseases (Dickerson 1999; Fuchs 2002; Tilston et al. 2005). Hoitink et al.
(1997) argues about “t wo classes of biological control mechanisms known as "general" and "specific"
suppression that have been described f or compost -amende d substra tes. The mechanisms involved are
based on competition, antibiosis, hyper par asitism and the induction of systemic acquired resistance in
the host plant ”.
The use of compost as an alternative to fumigation, has gained the attention of both farmers and
scien tists alike . However, the limited knowledge over the influence of compost usage on the soil
biological communities and microbial and metabolic dynamics, doesn’t confer this practice full trust
among farmers.
When it comes to disease suppressiveness , St. Martin(2015) argues that a higher level was observed
where compost mixes were applied before every two croppings compared to those applied only at
planting. Moreover, referring to the absence or presence of residual, cumulative or delayed suppressive
effec ts, most studies show that where >50 % disease control was recorded, compost was applied at a
rate of at least 100 tons/ha (Coventry et al. 2006; Zaccardelli et al. 2011). The application of such high
rates , exceed s the established limit of 30 tons/ha for green composts and 20 –30 tons of green or food –
derived compost / ha set for nitrate vulnerable zones (NVZs) (Council Directive 91/676/EEC 1991).
Furthermore , these rates can become potentially hazardous to the environment, especially in relation to
groundwa ter and surface water pollution and the conveyance of heavy metals to the soil.
Another limitation in using compost as disease suppression method, is the possibility to replicate and
standardize the compost quality across production batches and differences in climate, soil type, crop
production practices and/or experimental protocols used in the field . (St. Martin,2015) . Till today , this
has been one of the important impediments in making compost a recommended method against
diseases when it comes to commer cial crop production (St. Martin,2015) .
As Stone et al. (2004 ) suggests,” inducing general or specific suppression in soils using compost or
compost tea might not be sufficient or possible to achieve commercially viable disease control in many
disease and cropping systems . In such cases, other strategies or combinations of strategies such as the
use of crop rotation, cover and rotation crops, tillage and inputs including plant genetic resources and
amendments will be necessary ”.

2.4 Using resistant strains

It is known that many strains of fruit trees like M27 apples, ‘Colt’ cherries or Myrobalan B plums are
more resistant to replant disease than others.

2.5 Testing the soil

Soil tests could provide vital informati on on Ph levels, soil fertility and micr obial communities . It is
recommended that the soil testing and analysis be carried out a year before planting. This will allow the
grower s ufficient time to determine fertilizer requirements as well as whether any specific adjustments
are required to the s oil Ph levels. At the same time, an overview of the soil -borne pathogens present in
the tested area would give valuable insights on grower’s future decisions.

Apple Replant Disease – Theory versus practice, an overview of known controlling methods
H. Meints & A. Toma

2.6 Removing old plant m atter

It is advised to e nsure the removal of old plant material as soon – and as thoroughly – as possible, while
taking special care to remove all traces of roots during this process.

2.7 Grow ing ‘Break Crops’

When possible, avoid ing replanting similar species in the same spot might be helpful . For many, this may
not be pra ctical, but growing a ‘break crop’ can often play a vital role in prevention, as Stelljes (2000)
argues. Following the ‘Pomes and Stones’ rule can also prove effective , meaning that instead of
following a ‘Pome’ fruit with a fruit from the same group, a ‘Stone’ fruit should be a good replacement
crop . This method is not guaranteed, as these trees can still be susceptible t o non -specific replant
disease (w hich affects Pomes trees that are planted after Stone crops, and vice -versa ).

2.8 Fumigat ing the soil

Apparently, s oil fumigation lead s the fight agains t ARD, with several treatment options available on the
market, depending on the crop in question. Methyl Bromide was once commonly used to control apple
replant disease in the 90’s, but has since been phas ed out for years now (due to environmental
concerns), leaving the role to other alternative products such as Chloropicrin , the most used one . This
specific fumigant proved to be e ffectiv e combatant in the war against ARD as studies shown (Line,2005) .
But pre-plant fumigation has also its disadvantages as it negatively impacts on the health and diversity
of soil biological communities (Hoagland et al,2012). Another example of “two faced” product is metam –
sodium, a fumigant commonly used also to treat apple replant disease, which has been found to disrupt
beneficial free -living nematodes, mycorrhizae, and beneficial bacteria and fungi that cycle nitrogen (Cox,
2006). Additionally, this chemical is a carcinogen that can negatively impact farm worker health (Co x,
2006).

2.9 Alternative methods on fighting ARD

The need to find effective strategies in combating apple replant disease emerged over years, as
continuum research takes place . Through the lab and field trials, different lessons have been learnt in
time and related reports were published to share the knowledge. For instance, methods like d igging
holes and filling them with imported soil that is free of the causal pathogens is not cost -effective in a
large orchard, and proved to only control disease sympt oms for the first year or two (Anonymous,
2001). At the same time, l eaving soil fallow for an extended period of time has also been ineffective in
controlling the causal pathogen complex (Mazzola and Mullinix, 2005; Fuller, personnel
communication).

2.10 Anaerobic Soil Disinfestation
Anaerobic soil disinfestation (ASD) which may also be known as ‘biological soil disinfestation’ or
‘reductive soil disinfestation’ represents a pre -plant (non-chemical) soil disinfestation technique and is
more often proposed as an alternative to chemical soil fumigation (CSF) when it comes to controlling
several soil -borne diseases, plant -parasitic nematodes, and weeds in different vegetables and fruit crops
(Shennan et al. 2014; Rosskopf et al. 2015).

Apple Replant Disease – Theory versus practice, an overview of known controlling methods
H. Meints & A. Toma
After being developed in dependently in Japan (Momma et al., 2013) and The Netherlands (Blok et al.,
2000), for both open field and protected crops , ASD has gained interest all over the world (Shennan et
al., 2014).
1Number of studies by country and USA sta tes and response variables examined. Shrestha et al (2016)

“The principle of the technique is to create a temporary anaerobic soil environment to stimulates the
growth of facultative and obligate anaerobic microorganisms, that under anaerobic conditions,
decompose the available carbon (C) source, producing organic acids, aldehydes, alcohols, ammonia,
metal ions, and volatile organic compounds, that are suppressive or toxic for several soil -borne pests
and diseases “(Momma 2008; Huang et al. 2015; van Agtm aal et al. 2015).
In the scientific literature, ASD is described as having three stages : 1) amending the soil with a readily
decomposable C source to initiate rapid soil microbial growth and respiration, 2) covering the bed with
oxygen impermeable polyethy lene mulch to prevent the diffusion of oxygen from the soil surface, 3)
irrigating the soil to saturate the pore space and further reduce the presence of oxygen (Butler et al.,
2014; Shennan et al., 2014).
3. Experiments and their outcomes
In the past decad es, many scientists conducted laboratory and field trials , experimenting ways to
prevent and control ARD. From testing the efficiency of chemical products to exploring eco -friendly
alternatives, all those initiatives came to their very own conclusions. In Shrestha et al (2016), an in-depth
analysis was conducted, reviewing a consistent number of publications related to ASD. Their work
suggests that anaerobic soil disinfestation “can work as a replacement to chemical fumigants for
pathogen suppression as we observed consistent pathogen suppression under various conditions ”. They
also identified that ASD treatments proved to be more effective under higher soil temperature for both
nurseries and field conditions. For example, having a soil temperature above16°C can influence the
incubation period, which can be reduced to less than 3 weeks . However, under low temperature
(<16°C), ASD can be effective when certain factors are modified, for e.g., Ralstonia and Verticillium
under low temperature were effectively sup pressed when higher amendment rates (grass) and longer
incubation periods of 10 to 25 weeks were practiced (Shrestha et al, 2016) .

Apple Replant Disease – Theory versus practice, an overview of known controlling methods
H. Meints & A. Toma
Another aspect to be considered is the
difference between the levels of pathogens
suppression level conducted in as potting
soil or other laboratory media and results
obtained under field conditions. In Shrestha
et al (2016) it is mentioned that “a mong
various types of soil, clay and sandy soils
showed low suppression of pathogens in
response to ASD treatment. Reasons for this
observation may include low availability of C
to microorganisms due to rapid loss of
soluble C in sandy soil and greater
adsorption and reduced water infiltration
rate that affects the distribution of
decomposition by -products in clay soils. Clay
soils ar e also likely to be more buffered
against changes in soil pH that may affect
the accumulation of VFAs. Further, these
acids are weakly adsorbed to the soil’s
exchange phase and have rapid turnover
rate with short half -life ( Jones et al., 2003 )
and transito ry when exposed from
anaerobic to aerobic condition ( Lazarovits
et al., 2005 ). Whereas volcanic ash, loam and gray lowland soil showed more suppression than clay and
sand as these soils are themselves more fertile with high mineral contents which often enh ance
microbial activity ”.
Experiments showed that a major
benefit of ASD is that it can control
pathogens under relatively short
incubation periods: for an incubation
period <3 weeks – 77% pathogen
control, depending on study type and
soil type. As previou s studies argue,
incubation periods below3 week s were
reported from small -scale studies,
including lab studies and only few
large -scale studies, which included
volcanic ash and gray lowland studies
(Shrestha et al,2016).

2 Comparisons among levels of (A) crop type, (B) study type, (C) soil type, (D) soil
temperature, and (E) incubation period; Number of studies reporting data for
each level of moderator is given in parentheses (Shrestha et al,2016).
3 Comparisons among levels of (A) forms, (B) mixed, (C) types, (D)
unamended and (E) Rate per m2. Numbe r of studies reporting data for
each level of moderator is given in parentheses (Shrestha et al,2016)

Apple Replant Disease – Theory versus practice, an overview of known controlling methods
H. Meints & A. Toma
Further, we will summarize and review the experiments we consider to be relevant for our topic.

3.1 A closer look over microbial community development

Rumberger et al (2007) conducted their research on an orchard site that was originally planted with
apple trees around 1910 and then replanted in 1981 with trees grafted on M.9/M.106 and M.9/M.111
rootstocks (M.111 and M.106 roots with an M.9 interstem). The second planting established poorly and
exhibited many symptoms of ARD (Mai et al., 1994). Rumberger et al (2007) argue that using ARD –
tolerant rootstocks is an emerging control strategy. Therefore, they studied the bacterial, fungal, and
oomycetes populations in the rhizosphere of five rootstock cultivars (M.7, M.26, G.16, G.30 and
CG.6210) “planted into the old tree row or grass la nes
of a previous orchard in Ithaca, NY, to better
understand the role of rhizosphere microbial
communities in the prevalence and control of ARD ”.
Their observations after a period of 3 years, revealed
that microbial densities were highest in July, lower i n
May and lowest in September. Moreover, the study
showed that the composition of bacterial and fungal
communities in the rhizosphere was highly variable and
changed over seasons and years, as assessed by
terminal restriction fragment length polymorphism ( T-
RFLP) analyses (Rumberger et al, 2007) . Their research
paid attention at the changes in terms of fungal
rhizosphere communities , which from initial differences
between the planting positions 2 years later , after the
trees were replanted , they converged. At the same
time , the bacterial rhizosphere community maintained
its difference in numbers between the planting
positions, even 3 years after the orchard was replanted.
In their study, Rumberger et al (2007 ) observed that just as mentioned before by Catsk a et al. ( 1982),
the densities of Pseudomonas in the apple rhizosphere decreased over years after replanting, whereas
population shifts may be related to changes in soil moisture, soil temperature, rhizodeposition and/or
root turnover (Yao et al., 2006b).
Their conclusion was that tree growth and yield data obtained from the studied orchard (Rumberger et
al., 2004; Leinfelder and Merwin, 2006) suggest that “avoiding replanting into the old tree rows coupled
with the use of tolerant rootstocks are useful st rategies for reducing ARD in replanted orchards ”.
Furthermore, they found that t he susceptible rootstocks, M.26 and M.7, supported higher densities of
culturable bacteria and fungi in their rhizosphere than the rootstocks G.16, G.30 and CG.6210 .

Figure 1 – fingerprints of the bacterial community in
rhizosphere soil (reproduced from Rumberger et al, 2007)

Apple Replant Disease – Theory versus practice, an overview of known controlling methods
H. Meints & A. Toma

3.2 Whe at – the chief mediator

Apple replant disease proved to be a major
impediment to organic orchard production systems.
(Hoagland et al,2011). Because studies shown that it
might be caused by soil-borne pathogens and
parasites that are built in the soil of an orchard over
time and due to the consequences of this dieses,
many orchardists withdrawn their organic certification
and used pre -plant fumigation to remediate soil -borne
pathogens prior to planting new apple trees (Hoagland
et al,2012). As an a lternat ive to chemical products,
research over the positive effects of planting wheat
prior to planting apple trees was conducted.1 Trials
revealed that “beneficial soil microbial communities”
were increased after wheat was planted in the orchard
soils, which res ulted in suppressing soil -borne
pathogens and visible improvements in apple seedling health. Wheat varieties bred under organic
conditions had the best results, as Hoagland et al (2011) noted upon their research .
The conclusion of their trials was that “including only one year of annual wheat cultivation after removal
of an existing apple orchard can increase
beneficial soil microbial species, suppress soil –
borne pathogens and parasites, and improve the
establishment and productivity of newly apple
planted trees. These results support the
hypothesis that modification of soil microbial
community composition likely plays a role in
disease suppression following cover crop
cultivation ”.

3.2 Brassica seed meal amendments as alternative to soil fumigation

In the early ‘90s, Dr. Mark Mazzola joined the Agricultural Research Laboratory in Wenatchee,
Washington to focus his research on control methods of the ARD2. Over years, he conducted several
field trials using and comparing different strategies to fight repl ant disease. He noticed that fumigation
with chemical s, such as Telone C -17, only provides short -lived control of harmful soil organisms , while

1 Hoagland, L., Mazzola, M., Murphy, K.M., Jones, S.S., 2012. Wheat varietal selection and annual vs. perennial growth habit impact soil
microbial community and apple replant disease
suppression. Organic Seed Alliance Conference, Port Townsend, WA. pp. 13 -15
2 http://www.goodfrui t.com/new -replant -disease -treatment
Figure 3-Impact of wheat cultivation on (reproduced from
Hoagland et al,2011)
Figure 2 – Apple growth in pot previously planted to wheat
(control left, organic wheat cultivar right) (July,2009); reproduced
from Hoagland et al (2011)

Apple Replant Disease – Theory versus practice, an overview of known controlling methods
H. Meints & A. Toma
there are other alternatives for” longer lasting effects and even greater benefits than fumigation in
terms of b oth tree growth and fruit yields ”.
One of the solution Dr. Mazzola found to be effective is Brassica seed meal amendment ( SM) that can
provide control of numerous plant pests through generation of biologically active glucosinolate
hydrolysis products or in directly via t ransformation and activity of the resident soil biology
(Mazzola&Zhao, 2010) . In Mazzola et al. (2014) it is described how field trials were conducted to
determine the effect of SM formulation, moment of application and apple rootstock on the ir efficiency
against ARD. In their study, they used treatment plots of 10,7m/2m, with five replicates per treatment,
comparing preplant soil fumigation ( using Telone -C17) with Brassica SM formulations.
As presented by Mazzola et al. (2014), tree performa nce in SM -amended soil was “commonly superior
to that in fumigated soil at the end of four
seasons”. Moreover, they observed an
increased resistance to reinfestation in SM –
amended soils and that the rhizosphere
microbiome gained “unique bacterial and
funga l profiles, including microbial elements
previously associated with suppression of
plant pathogens”
The study concluded that using Brassica SM
formulations apple replant disease can be
fought as shown by the growth of the trees
and increased yields. Mazzo la’s research also
showed that the SM applications can provide
weed control, as well as (like the metagenome
analyses revealed) generating higher
populations of bacteria that can metabolize
toxic organic compounds (this may enable
degradation of pesticides applied to the
orchard ).

3.3 Herbie – an efficient fighter against soil borne pathogens

Between 2004 and 2009 the Dutch company Thatchtec developed, in collaboration with Wageningen
UR, a new method for biological soil decontamination(sRset). The met hod consists of the introduction of
100% plant -based Herbie -granulates (or liquid) into the soil, followed by covering the soil with foil for 3
to 4 weeks. According to the tests the company made, it was shown that after this period, the ground is
usually free of nasty diseases caused by damaging nematodes, molds and insects (in Annex 1 are
described the conditions and results of the field tests on apple trees, conducted by Laimburg Research
Centre for Agriculture and Forestry, Italy in 2016 ; the trials inc luded the use of different methods and
products such as steaming, solarisation, chemical and biofumigants – including Herbie).
reproduced from Mazzola et al. (2014) 1

Apple Replant Disease – Theory versus practice, an overview of known controlling methods
H. Meints & A. Toma
Thatchtec, through the Soil Resetting division , started in 2014 a close collaboration with Fleuren Tree
Nursery in Kessel , Limbur g province (The Netherlands) , conducting a field trial with a duration of two
years. The aim of the experiment was to reproduce the tests described by Mazzola (2010;2014;2015)
using Herbie as mediation product in apple replant disease control. Plant behavi or was closely observed
and the results were visible positive in the areas where the soil was amended.

picture of apple trial 2014 -2016 1- photo summer 2016 by H.Mei nts

In March 2017 , a new field tr ial was agreed for the same location but with more ambitious objectives. In
the following two years, a total surface of 990m2 will be divided into eight lots of 8m per 15m, with an
added buffer zone of 2m per 15m , while the dosage of Herbie per treatment p lot will be 322 kg, plus a
half dosage plot . The control area will be left untreated. Comparing with the reported figures in Mazzola
(2014), the selected surface for testing plots at Fleuren Boon, is by far larger. It was decided on purpose
to use these bi gger scales aiming at an increased validity for the future test results, as Thatchtec
reported. Furthermore, a closer attention will be paid at the soil biology and tree performance (growth
and yields) during different seasons. The hypothesis is that creat ing the proper anaerobic condition s in
the soil depends on the outside temperature , period of the year and the moment of replanting.
Therefore, the first planting moment(PL1) will take place four weeks after removing the sealing foil3 .
However, the second moment of planting (PL2) has been chosen for April 2018.

3 The trial will use foil covering periods of 4,8 and 12 weeks

Apple Replant Disease – Theory versus practice, an overview of known controlling methods
H. Meints & A. Toma

The major difference between this trial session and the previously conducted one in 2014, is that now
temperature will play a key role (observing the results under high to low values) and the dosage will vary
(decrease) from 2,4 to 1,2 kg / m2) .
One of the questions that this research is willing to answer according to Thatchtec is: when can the
previous test results be obtained along the trial period ( in relation with the timeframe and external
factors)?

satellite pictures of the tested area 1- Meints (2017)

Apple Replant Disease – Theory versus practice, an overview of known controlling methods
H. Meints & A. Toma
4. Conclusion and recommendations

In the past decades, several researchers focused their attention on identifying the causes of Apple
Replant Disease, along with finding new strategies to prevent and control this important threat to fruit
production. From leaving the land fallow, using rotation and control crops to soil fumigation and organic
amendments, all has been considered over time. Nowadays, there is a visible tendency on using
environmental f riendly solutions, along with an increase in banning regulation regarding the chemical
products used in EU agriculture sector. Therefore, solutions such as Brassica seed meal soil amendments
developed by Mark Mazzola, or Herbie invented by Thatchtec in The Netherlands are the proof that
alternatives exist and can be efficient. However, like any other practice, they all have limitations in terms
of knowledge and it is mandatory to conduct further research in order to improve their approach. Both
Mazzola and Thatchtec aim at increasing the performance of SM and respectively Herbie, when it comes
to dosage, waiting time (till removing the sealing foil) and moment of planting the trees. By using larger
surfaces for the field trials, as well as testing the method in different times of the year, together with
multi -DNA tests (to monitor the soil biodiversity), all these give a valuable insight over the complexity of
replant disease. Thus, for fighting it we need the proper (and as complete as possible) knowledge, w hich
can only be gained by exploring, experimenting, (re)inventing till the field tests reach saturation.
As Kelderer et al (2017) describes in their report over the Core Organic 2 Project Bio -Incrop in
Laimburg(see also Annex ) and previously discussed ab ove, using soil amendments like Brassica SM or
Herbie developed by Thatchtec, has resulted in an almost 100% pathogen suppression and significant
increase in trunk circumference and yield . However, in the case of Herbie and particularly in the trials
condu cted at Fleuren Tree Nursery in Baarlo, experiments are pushed to their extremes trying to
monitories the method’s efficiency and limitations, regarding time frames, larger range of temperature
and dosage. What differentiate this later trial from the ones conducted by Mark Mazzola in the US, is
that at Fleuren, testing lots are bigger and a special attention is given to replicating the trials in various
season conditions. So far, the results obtained ga ve a positive trend and special attention should be pai d
not only to the unpredictable weather conditions and temperature from the first half of the year (that
were obviously different from the usual values) that can affect the trials, but also try to observe and
monitor the soil biodiversity along the tests, complementary to the plant behavior. This way we will not
only be able to draw conclusions on the apple tree health but also on the changes that occur in the soil
and how can Herbie influence the development of soil communities.
Another suggestion for fut ure tests and research could be the usage of mixt disease control methods ,
such as sRset and compost, to observe whether they can be complementary or not. It would be
interesting to investigate as well if adding compost to the disinfected soil, will have a ny effect on the
dosage of Herbie applied for the t reated surfaces, the plant development or yield. This aspect can
influence directly the commercial side of using sRset as a viable and accessible method to a larger scale.

Apple Replant Disease – Theory versus practice, an overview of known controlling methods
H. Meints & A. Toma
Field trial 2017 -2019 1 – photo Toma (2017) 5 Field trials photos

Apple Replant Disease – Theory versus practice, an overview of known controlling methods
H. Meints & A. Toma

Field trial 2017 -2019 2 – applying and incorporating Herbie – photo Toma (2017)

Apple Replant Disease – Theory versus practice, an overview of known controlling methods
H. Meints & A. Toma
Field trial 2017 -2019 3 – testing the incorporation level, digging and covering with foil – photo Toma
(2017)

Apple Replant Disease – Theory versus practice, an overview of known controlling methods
H. Meints & A. Toma
6. Annex 14

Field test results over apple tree performance and soil analysis in the Northern part of Italy.

Department of Ecological Agriculture – VZ Laimburg – 2016

File: BioIncrop
Year of experiment : 2016
Subject : Ground fatigue field test
Test facility : Block 93
Variety / Subsistence : Pink Lady M9
Planting distance 3,2 x 1 m
Experiment Design : 12 variants, 4 replicates of 13 -15 trees per 2 edge trees
A soil – weary experimental plant (previous variety: Br aeburn on M 9, planting distance 3,2 x 1 m,
planting year 1998) was carried out with different measures and different products.

Test subjects:

4 All the data and graphics in the current annex were translated and reproduced from the original report provided by Laimburg
Research Centre for Agriculture and Forestry , Italy to Thatchtec BV

Apple Replant Disease – Theory versus practice, an overview of known controlling methods
H. Meints & A. Toma

Description:

Compost analyzes :

Apple Replant Disease – Theory versus practice, an overview of known controlling methods
H. Meints & A. Toma
The c ompost was made of organic materi al and wood shavings – 3 kg / tree and was added to the plant
hole during planting .

Fertilizing the plant 2016 :
04.04.2016 Nitramoncal 29 N kg/ha
04.05.2016 Fertigonia 18 -18-18 10,3 N kg/ha
20.06.2016 Fertigonia 18 -18-18 3,4 N kg/ha

Product description : Herbie 82 (dry plant -based product)
It was used for introducing it into the moist soil and hermetically covered with foil upon proper mixing .
The expected result was to create anaerobic conditions and enable fermentation process into the soil .

Dates from Thatchtec B.V over Herbie : Analyzes of Laimburg Agricultural Chemistry Laboratory :

Ash: 4 -5% Trockenmasse (%) 89,6
Dry weight: 90 -95% Feuchtigkeit (%) 10,4
Protein: 20 -26% Asche (% FM) 6,5
Fiber: >10% Organische Substanz (% FM) 83,1
Sugars: 4 -6% Stickstoff (N) (% m/m) 2,58
Starches: 2 -3% C/N-Verhätlnis 19
Ph: 4,5 -5 Wasserlösliche S alze (mg/100 g) 810
Arsen (As) (mg/kg FM) 1,1
Eisen (Fe) (g/kg FM) 0,07
Aluminium (Al) (g/kg FM) 0,02
Mangan (Mn) (mg/kg FM) 31,07
Kupfer (Cu) (mg/kg FM) 6,31
Zink (Zn) (mg/kg FM) 29,06
Chrom (Cr) (mg/kg FM) 1,17
Nickel (Ni) (mg/kg FM) 0,62
Blei (Pb) (mg/kg FM) < 0.01
Cobalt (C o) (mg/kg FM) < 0.01
Cadmium (Cd) (mg/kg FM) 0,07
Quecksilber (Hg) (mg/kg FM) 0,005

What has been done:
– 1 month before planting, 3.4 kg / m² of Herbie was incorporated in the tree strip in the damp soil

– The soil was covered with film and w ell-sealed

Apple Replant Disease – Theory versus practice, an overview of known controlling methods
H. Meints & A. Toma

In 2015, the 2nd planting was carrie d out on the solarized area and in the control area .

Table soil analysis on 11.03.2015 :

Evaluations:
Figure 3:
Drive length measurement in cm in the open air
1. Measurement: 14.01.2015
2. Mea surement: 10.11.2015

Apple Replant Disease – Theory versus practice, an overview of known controlling methods
H. Meints & A. Toma

Figure 4:
Stem growth measurements (diameter) in mm in the open air
1. Measurement after planting: 20.06.2014
2. Measurement in autumn: 19.11.2014
3. Measurement in the autumn: 10.11.2015
4. Measurement in autumn: 06.12 .2016

Figure 5:
Harvest 03.11.2016 Number of apples / tree

Apple Replant Disease – Theory versus practice, an overview of known controlling methods
H. Meints & A. Toma

Figure 6:
Harvest 03.11.2016 KG Apples / tree

Apple Replant Disease – Theory versus practice, an overview of known controlling methods
H. Meints & A. Toma

7.References
Blok, W.J., Lamers , J.G., Termorhuizen , A.J. & B ollen G.J. (2000). Control of soilborne
plant pathogens by incorpo rating fresh organic amendments followed by tarping
Phytopathology, 90: 253 -259.

Brown PD, Morra MJ (1997) Control of soilborne plant pests using glucosinolate -containing plants. Adv
Agron 61:167 – 231

Brown J, Davis JB, Erickson DA, Seip L, Gosselin T (2 004) Registration of ‘Pacific Gold ’ condiment yellow
mustard. Crop Sci 44:2271 –2272

Catska, V., Vancˇura, V., Hudska´ , G., Prˇikryl, Z., 1982. Rhizosphere micro -organisms in relation to the
apple replant problem. Plant and Soil 69, 187 –197. B

Council Dir ective 91/676/EEC (1991) Protection of waters against pollution caused by nitrates from
agricultural sources. Off J L 375:1 –8

Dickerson GW (1999) Damping -off and root rot. BioCycle 40:62 –63

Hoagland et al., 2011.B iological Mediation of Apple Replant Dise ase in Organic Apple Orchards

Hoagland, L., Mazzola, M., Murphy, K.M., Jones, S.S., 2012. Wheat varietal selection and annual vs.
perennial growth habit impact soil microbial community and apple replant disease suppression. Organic
Seed Alliance Conferenc e, Port Townsend, WA. pp. 13 -15

Hoestra H 1968 Replant diseases of apple in The Netherlands. Meded. Landbouwhogesch. Wageningen
68-13. 105 p.

Hoitink H, Stone A, Han D (1997) Suppression of plant diseases by composts. HortSci 32 (2):184 –187

Huang, X., W en, T., Zhang, J., Meng, L., Zhu, T., and Cai, Z. (2015). Toxic organic acids produced in
biological soil disinfestation mainly caused the suppression of Fusarium oxysporum f. sp. cubense.
BioControl 60, 113 –124. doi: 10.1007/s10526 -014-9623 -6

Jones, D. L ., Dennis, P. G., Owen, A. G., and van Hees, P. A. W. (2003). Organic acid behavior in soils –
misconceptions and knowledge gaps. Plant Soil 248, 31 –41. doi: 10.1023/A:1022304332313

Kelderer, M et al (2017) , Efficacy evaluation of steaming, plant extracts a nd composts in open field trials
to reduce apple replant disease retrieved from w ww.ecofruit.net/2016/13_Kelderer_103bis107.pdf on
24-05-2017

Klerkx,L et al (2012) Evolution of systems approaches to agricultural innovation: concepts, analysis and
interven tions Communication and Innovation Studies, Wageningen Universit y, Wageningen , The
Netherlands

Apple Replant Disease – Theory versus practice, an overview of known controlling methods
H. Meints & A. Toma

Lazarovits, G., Conn, K. L., Abbasi, P. A., and Tenuta, M. (2005). Understanding the mode of action of
organic soil amendments provides the way for improved ma nagement of soilborne plant pathogens.
Acta Hortic. 698, 215 –224. doi: 10.17660/ActaHortic.2005.698.29

Litterick A, WoodM(2009) The use of composts and compost extracts in plant disease control. In:
Walters D (ed) Disease control in crops: biological and environmentally friendly approaches. Wiley –
Blackwell, Oxford, pp 93 –121

Litterick AM, Harrier L, Wallace P, Watson CA, Wood M (2004) The role of uncomposted materials,
composts, manures, and compost extracts in reducing pest and disease incidence and seve rity in
sustainable temperate agricultural and horticultural crop production —a review. Crit Rev Plant Sci
23(6):453 –479

Mazzola, M., 1998. Elucidation of the microbial complex having a causal role in the development of
apple replant disease in Washington. Phytopathology 88, 930 –938.

Mazzola, M., 1999. Transformation of soil microbial community structure and Rhizoctonia suppressive
potential in response to apple roots. Phytopathology 89, 920 –927.

Mazzola, M., Gu, Y. -H., 2002. Wheat genotype -specific induc tion of soil microbial communities
suppressive to disease incited by Rhizoctonia solani anastomosis group (AG) -5 and AG -8.
Phytopathology 92, 1300 –1307.

Mazzola M, Mullinix K. 2005. Comparative field efficacy of management strategies containing Brassica
napus seed meal or green manure for the control of apple replant disease. Plant Dis 89:1207 –13.

Mazzola, M., Funnell, D.L., Raaijmakers, J.M., 2004. Wheat cultivarspecific
selection of 2,4 -diacetylphloroglucinol -producing fluorescent Pseudomonas species fr om resident soil
populations. Microbial Ecology 48, 338 –348.

Mazzola M, Brown J, Zhao X, Izzo AD, Fazio G (2009) Interaction of brassicaceous seed meal and apple
rootstock on recovery of Pythium spp. and Pratylenchus penetrans from roots grown in replant soils.
Plant Dis 93:51 –57

Mazzola et al., 2015. Brassica seed meal soil amendments transform the rhizosphere microbiome and
improve apple production through resistance to pathogen re -infestation. Phytopathology 105:460 -469

Mazzola M, Freilich S, 2016. Pro spects for soil borne disease control: Application of Indigenous versus
Synthetic Microbiome. Phytopathology 107:256 -263

Momma, N., Kobara, Y., Uematsu, S., Kita, N., and Shinmura, A. (2013). Development of biological soil
disinfestations in Japan. Appl. Microbiol. Biotechnol. 97, 3801 –3809. doi: 10.1007/s00253 -013-4826 -9

Rumberger, A., Yao, S., Merwin, I.A., Nelson, E.B., Thies, J.E., 2004. Rootstock genotype and orchard
replant position rather than soil fumigation or compost amendment determine tree growth and
rhizosphere bacterial community composition in an apple replant soil. Plant and Soil 264, 247 –260.

Apple Replant Disease – Theory versus practice, an overview of known controlling methods
H. Meints & A. Toma

Rumberger et al. / Soil Biology & Biochemistry 39 (2007) 1645 –1654

Sachbereich Ökoanbau – VZ Laimburg – 2016
Shennan, C., J. Muramoto, M. Mazzo la, N. Momma, Y. Kobara, J. Lamers, E.N. Rosskopf, N. Kokalis –
Burelle and D.M. Butler. 2014. Anaerobic soil disinfestation for soil borne disease control in strawberry
and vegetable systems: Current knowledge and future directions. Acta Horticulturae 1044: 165-175.

Shrestha U, Augé RM and Butler DM (2016) A Meta -Analysis of the Impact of Anaerobic Soil
Disinfestation on Pest Suppression and Yield of Horticultural Crops. Front. Plant Sci. 7:1254. doi:
10.3389/fpls.2016.01254
St. Martin CCG (2015) Enhancing S oil Suppressiveness Using Compost and Compost Tea . Springer
International Publishing Switzerland 2015 M.K. Meghvansi, A. Varma (eds.), Organic Amendments and
Soil Suppressiveness in Plant Disease Management, Soil Biology 46, DOI 10.1007/978 -3-319-23075 -7_2

Stone A, Scheuerell S, Darby H, Magdoff F, Ray R (2004) Suppression of soilborne diseases in field
agricultural systems: organic matter management, cover cropping, and other cultural practices. In:
Magdoff F, Weil RR (eds) Soil organic matter in sustaina ble agriculture. CRC Press, Boca Raton, pp 131 –
177

Tilston E, Pitt D, Fuller M, Groenhof A (2005) Compost increases yield and decreases take -all severity in
winter wheat. Field Crops Res 94(2):176 –188

Traquair J A 1984 Etiology and control of orchard rep lant problems: A review. Can. J. Plant Pathol. 6, 54 –
62.

Van Schoor L, Denman S, Cook N (2009) Characterisation of apple replant disease under South African
conditions and potential biological management strategies. Sci Hortic 119 (2):153 –162

http://www. soilresetting.com/
Zaccardelli M, Perrone D, Pane C, Pucci N, Infantino A (2011) Control of corky root of tomato with
compost and role of spore -forming bacteria to inhibit Pyrenochaeta lycopersici. Acta Hortic (ISHS)
914:393 –396