Botrytis Fruit Rot Control Research Articles

Integrating management of powdery mildew with Botrytis in protected strawberries in the UK

Powdery mildew, caused by Podosphaera aphanis, is an important disease of strawberries under protection. Botrytis fruit rot is an important cause of losses in strawberries particularly under open-field conditions. Current control of both these diseases in the UK is dependent on conventional fungicides. Recently, research in the UK demonstrated that integrating biopesticides and biostimulants with a decision-based management programme could achieve reductions in conventional fungicide use without loss in yield or fruit quality. Further field studies were conducted to extend the decision-based management programme to include control of Botrytis fruit rot on everbearer crops. In 2018, three management programmes were compared to a routine fungicide-based programme and an untreated control. In two management programmes, treatments for Botrytis and powdery mildew were either applied routinely or managed. In the third programme, treatments for both diseases were managed. Disease risks were estimated with a simple lookup table based on past and forecast weather. The results showed that the integrated management for both diseases resulted in a nearly 45% reduction in conventional fungicide use and a cost saving of £699/ha compared to a routine programme with no penalties in yield, fruit quality or disease control. There were no significant effects of treatments on Botrytis rot incidence compared to the untreated control, suggesting that the fungicides applied for controlling Botrytis gave no benefit. In 2019, two treatments based on the decision-based management system for powdery mildew and Botrytis, one of which excluded specific fungicide treatment for Botrytis, were compared to an untreated control and a routine fungicide programme. Cool chain management of the fruit post-harvest was also included to extend post-harvest fruit shelf life. The results showed that the simple decision-based system for determining treatments for mildew and Botrytis based on biopesticides and omitting Botrytis-specific fungicides resulted in a 93% reduction in fungicide use and a cost saving of £924/ha compared to a routine programme with no penalties in yield, fruit quality or disease control. Cool chain management delayed the development of both Botrytis and soft rots. In both years, detectable fungicide residues were considerably reduced in the fruit from the managed programmes.

Erratum: The Importance of Selecting Appropriate Rotation and Tank-Mix Partners for Novel SDHIs to Enhance Botrytis Fruit Rot Control in Strawberry

Erratum: The Importance of Selecting Appropriate Rotation and Tank-Mix Partners for Novel SDHIs to Enhance Botrytis Fruit Rot Control in Strawberry

The Importance of Selecting Appropriate Rotation and Tank-Mix Partners for Novel SDHIs to Enhance Botrytis Fruit Rot Control in Strawberry.

Botrytis fruit rot (BFR), caused by the necrotrophic fungus Botrytis cinerea, is the most important disease of strawberry and is mainly controlled by applications of fungicides from multiple chemical groups. To develop more effective and sustainable BFR management programs, field trials were conducted to evaluate the efficacy of fluopyram and penthiopyrad, two newly registered succinate dehydrogenase inhibitors (SDHIs), rotated or tank mixed with the multisites thiram and captan or the single-sites fludioxonil and fenhexamid. The treatments were applied at two different strawberry fields during the 2013-14 and 2014-15 seasons. Overall, tank mixtures of fluopyram and penthiopyrad increased yield and reduced BFR better than rotations with the same fungicides. The multisite thiram tank mixed with fluopyram reduced BFR incidence by 63 to 86% versus 56 to 84% when the two fungicides were rotated. Thiram tank mixed with penthiopyrad reduced BFR incidence by 55 to 72% versus 42 to 66% when rotated. Captan rotated or tank mixed with fluopyram had a positive effect on yield and BFR incidence, whereas the combination of captan with penthiopyrad had negative impacts. Similarly, the single-site fenhexamid had significant positive impacts when rotated or tank mixed with fluopyram but resulted in poor BFR control when combined with penthiopyrad. The rotation of fludioxonil with both SDHIs had a significant positive effect, although its combination with fluopyram was more effective. The multirotation consisting of both SDHIs and different multi- and single-site fungicides did not provide a greater efficacy than the dual rotation or tank-mixture programs. Our findings suggest more scrutiny is needed when recommending tank-mixture or rotation partners for new fungicides to ensure compatibility and enhanced BFR management. Future recommendations should emphasize the importance of such selections at an early stage for delaying fungicide resistance development and extending the lifespan of at-risk fungicides.

Evaluation of the Florida Strawberry Advisory System for Control of Botrytis and Anthracnose Fruit Rots in Ohio

The Florida Strawberry Advisory System (StAS) forecasts the need for fungicide applications for control of Botrytis fruit rot (BFR) and anthracnose fruit rot (AFR) based on leaf wetness and temperature during the moist period. StAS was evaluated in Ohio for four seasons from 2011 to 2014 and compared with the calendar-based system currently used by growers. BFR was severe in 2011 and 2013 and nearly absent in the other years, whereas AFR was not a problem in any of the four years. Using the calendar-based system, five to six applications were made each year for BFR, whereas only two or fewer were recommended using StAS. For AFR control, six to seven applications were made based on the calendar system, whereas three or fewer were recommended by StAS. There was no case in which the calendar program outperformed the StAS in disease management. Use of StAS would greatly reduce the number of sprays needed for control of fruit rot diseases and result in significant savings for Ohio strawberry growers.

Effectiveness of fungicide treatments following the Strawberry Advisory System for control of Botrytis fruit rot in Florida

Florida strawberry production is highly affected by plant diseases. Botrytis fruit rot (BFR) is an important disease that can cause more than 50% yield losses if not well-managed. The disease is traditionally managed in Florida by preventative fungicide applications using a multi-site fungicide in early season when environmental conditions are less conducive for disease development and single-site fungicides during bloom when the environment is more conducive. More recently, many Florida growers have been following the Strawberry Advisory System (StAS), a web-based disease forecast system, to improve timing and reduce the number of fungicide applications. In this study, we evaluated the effectiveness of different fungicides used after StAS spray alerts compared to Calendar-based applications with the objective of implementing specific fungicide recommendations for Botrytis control into StAS. Two field trials were conducted, one in 2013–2014, and the second in 2014–2015 season. During periods that predicted high risk of disease incidence, BFR was best managed by StAS-triggered applications of fludioxonil + cyprodinil, or fluopyram. Yields were increased by StAS-triggered treatments that included fludioxonil + cyprodinil, thiram and the SDHI fungicides fluopyram, penthiopyrad, and fluxapyroxad, and the Calendar-based treatment in one season. However, the StAS-triggered treatments had about half the number of applications of the Calendar-based program. Our results show that timing and the choice of the fungicide to be sprayed when weather conditions are highly favorable for disease development are key to effective management of BFR.

Evaluation of leaf wetness duration models for operational use in strawberry disease-warning systems in four US states.

Leaf wetness duration (LWD) plays a key role in disease development and is often used as an input in disease-warning systems. LWD is often estimated using mathematical models, since measurement by sensors is rarely available and/or reliable. A strawberry disease-warning system called "Strawberry Advisory System" (SAS) is used by growers in Florida, USA, in deciding when to spray their strawberry fields to control anthracnose and Botrytis fruit rot. Currently, SAS is implemented at six locations, where reliable LWD sensors are deployed. A robust LWD model would facilitate SAS expansion from Florida to other regions where reliable LW sensors are not available. The objective of this study was to evaluate the use of mathematical models to estimate LWD and time of spray recommendations in comparison to on site LWD measurements. Specific objectives were to (i) compare model estimated and observed LWD and resulting differences in timing and number of fungicide spray recommendations, (ii) evaluate the effects of weather station sensors precision on LWD models performance, and (iii) compare LWD models performance across four states in the USA. The LWD models evaluated were the classification and regression tree (CART), dew point depression (DPD), number of hours with relative humidity equal or greater than 90% (NHRH ≥90%), and Penman-Monteith (P-M). P-M model was expected to have the lowest errors, since it is a physically based and thus portable model. Indeed, the P-M model estimated LWD most accurately (MAE <2h) at a weather station with high precision sensors but was the least accurate when lower precision sensors of relative humidity and estimated net radiation (based on solar radiation and temperature) were used (MAE = 3.7h). The CART model was the most robust for estimating LWD and for advising growers on fungicide-spray timing for anthracnose and Botrytis fruit rot control and is therefore the model we recommend for expanding the strawberry disease warning beyond Florida, to other locations where weather stations may be deployed with lower precision sensors, and net radiation observations are not available.

Economic performance and comparative riskiness of different management practices for control of botrytis fruit rot in florida strawberry

Florida strawberry farmers usually rely on weekly calendar fungicide applications to prevent yield loss from Botrytis fruit rot (BFR). The Strawberry Advisory System (SAS), which helps optimize the timing of fungicide applications, is an additional tool in the farmers' arsenal of disease control options. This study uses data from two-year production trials in Florida combined with historical strawberry prices to measure the economic performance of the Calendar and SAS-based BFR management practices under output price risk and producers' risk preferences. We use Monte Carlo simulation to model the effect of the variability in weekly output prices on farm returns. Results reveal that the traditional calendar-based system is not the least risky BFR management option as growers expected to be. SAS-based options such as SAS-Switch and SAS-Luna would be preferred by both risk-neutral and risk-averse producers and are recommended under high disease pressure conditions.

The control of Botrytis fruit rot in strawberry using combined treatments of Chitosan with Zataria multiflora or Cinnamomum zeylanicum essential oil

This study evaluated the efficacy of the combined application of chitosan (CS) and Zataria multiflora (ZEO) or Cinnamomum zeylanicum essential oils (CEO) on the inhibition of Botrytis cinerea, the causal agent of strawberry gray mold on laboratory media and fruits during storage (7 days at 4 °C followed by 3 days at 20 °C). The application of different CS, CEO and ZEO concentrations inhibited the mycelial growth of the assayed fungus. The mixtures of CS and CEO (CC) or ZEO (CZ) inhibited the mycelia growth in potato dextrose agar, as well as the growth of B. cinerea in artificially infected strawberries stored at both room and cold temperature. Moreover, combined treatments showed more significant mycelial inhibition results and reduction of the IC50, MIC and MFC values compared to pure EOs or CS (p < 0.05). In fruit decay assays, combined treatments (CC or CZ) were able to reduce fungal decay in the range of 60–85 % at 9th day of storage. These results demonstrate the potential of the combined application of CS and CEO or ZEO at sub-inhibitory concentrations to control post-harvest pathogenic fungi in fruits, in particular, B. cinerea in strawberries.

Fungicide Resistance Profiles for 13 Botrytis cinerea Isolates from Strawberry in Southeastern Louisiana

Fungicidal sprays are widely used for control of Botrytis fruit rot; however, the pathogen often develops resistance to frequently used fungicides. A 96-well plate micro-dilution broth bioassay developed for fungicide discovery was used to provide strawberry growers with a rapid assessment of the fungicide sensitivity of Botrytis isolates against 16 fungicides. Three sensitivity phenotypes were identified: benzimidazole and dicarboximide resistant, benzimidazole resistant and dicarboximide sensitive, and an intermediate response to both fungicides. Codon at position 198 in the β-tubulin gene confirmed benomyl resistance. This bioassay rapidly identifies fungicide resistance and allows growers to quickly adjust their disease management strategy.

INFLUENCE OF WATER VOLUME AND DROP SIZE IN RASPBERRIES

The main disease in raspberries is Botrytis fruit rot. For a good control 3 or 4 treatments with chemicals during the flowering period are needed. A questionnaire in 2010 revealed that the raspberry growers use a wide range of water volumes (300 to 1000 L per hectare) and also apply different nozzles resulting in different drop sizes. In 2010 we started a project to optimize the chemical treatments in raspberries. We compared the application of 300, 600 and 900 L water per hectare with coarse and fine drop size respectively. We measured the deposition of the chemicals on leaves and evaluated the biological efficacy on Botrytis fruit rot and two-spotted spider mites. The deposition trials showed more chemicals on the leaves with the lowest water volume (300 L) and with coarse drop size. There was no correlation between the deposition on the leaves and the control of Botrytis fruit rot and the spider mites. All treatments gave a good result in controlling Botrytis fruit rot, with no differences between the variants. The spider mites live on the bottom side of the leaves. There was no efficient control from the different water volumes. Further trials showed a better efficacy, we used a water volume of 1.800 L per hectare and the air volume was increased from 25500 m 3 per hour to 35800 m 3 per

Control of Postharvest Botrytis Fruit Rot of Strawberry by Volatile Organic Compounds of Candida intermedia

A study was conducted to identify volatile organic compounds or volatiles produced by Candida intermedia strain C410 using gas chromatography-mass spectrometry, and to determine efficacy of the volatiles of C. intermedia in suppression of conidial germination and mycelial growth of Botrytis cinerea and control of Botrytis fruit rot of strawberry. Results showed that, among 49 volatiles (esters, alcohols, alkenes, alkanes, alkynes, organic acids, ketones, and aldehydes) identified from C. intermedia cultures on yeast extract peptone dextrose agar, two compounds, 1,3,5,7-cyclooctatetraene and 3-methyl-1-butanol, were the most abundant. Synthetic chemicals of 1,3,5,7-cyclooctatetraene; 3-methyl-1-butanol; 2-nonanone; pentanoic acid, 4-methyl-, ethyl ester; 3-methyl-1-butanol, acetate; acetic acid, pentyl ester; and hexanoic acid, ethyl ester were highly inhibitory to conidial germination and mycelial growth of B. cinerea. Inhibition of conidial germination and mycelial growth of B. cinerea by volatiles of C. intermedia was also observed. Meanwhile, results showed that incidence and severity of Botrytis fruit rot of strawberry was significantly (P < 0.01) reduced by exposure of the strawberry fruit to the volatiles from C. intermedia cultures or C. intermedia-infested strawberry fruit. These results suggest that the volatiles of C. intermedia C410 are promising biofumigants for control of Botrytis fruit rot of strawberry.

Effect of Timing of Preharvest Fungicide Applications on Postharvest Botrytis Fruit Rot of Annual Strawberries in Florida

Preharvest fungicide applications for postharvest control of Botrytis fruit rot were evaluated over four seasons on annual strawberry in Florida. In the 2002-2003 season, applications of Switch or Elevate immediately prior to harvest were ineffective for controlling Botrytis fruit rot postharvest. In the 2003-2004 season, applications of Captevate or Switch made immediately prior to harvest reduced postharvest Botrytis fruit rot, but not as much as applications made during the flowering period. Similarly, in the 2004-2005 season, Captevate and Pristine provided some control of postharvest Botrytis fruit rot when applied immediately before harvest. In both the 2003-2004 and 2004-2005 seasons, applications made during the flowering period were more effective for postharvest Botrytis fruit rot control than those made prior to harvest. In the 2006-2007 season, applications of Captevate, Thiram, Scala plus Captan, or Switch alternated with Captan during the flowering period provided good control of postharvest Botrytis fruit rot. Although not as effective as bloom applications, fungicides applied immediately before harvest may have some benefit for controlling Botrytis fruit rot if the sprays during the bloom period were not made. Accepted for publication 21 July 2009. Published 21 September 2009.

Biological Control of Botrytis Fruit Rot (Gray Mold) on Strawberry and Red Pepper Fruits by Olive Oil Mill Wastewater

ABSTRACTThe antifungal activity of olive oil mill wastewater (olive OMW) on Botrytis cinerea Pers was investigated. The effect of sterilized, filtered and non sterilized olive OMW was tested in vitro: a) on mycelium growth of B. cinerea on PDA agar plates and b) on strawberry and pepper fruits infected with the pathogen. The results show that the filter sterilized olive OMW inhibits the growth of B. cinerea mycelium in vitro probably due to the activity of the phenolic compounds contained on olive OMW. Furthermore, olive OMW significantly decreased fungus mold formation on the tested fruits.

Efficacy of Pre-harvest Fungicide Applications and Cold Storage for Postharvest Control of Botrytis Fruit Rot (Gray Mold) on Red Raspberry

Applications of the fungicides Elevate 50WG and Switch 62.5WG to red raspberry prior to harvest were evaluated for post-harvest control of fruit rot, caused by Botrytis cinerea. Fungicides were applied three times during bloom only, three times pre-harvest (post-bloom) only, or six times full season (bloom through harvest), and symptomless fruit (at harvest) were incubated for 8 days in either cold storage (4°C) or at room temperature (23°C). Without fungicide, between 6 and 29% of the fruit had rot symptoms after 2 days of storage at room temperature over the 2 years of testing; after 8 days, 74 and 85% of the fruit had symptoms at room temperature. Zero and 12% of fruit had symptoms with 2 days of cold storage when plants were not treated with fungicide, and rot incidence increased to 9 and 60% at 8 days of cold storage over the 2 years. All fungicide treatments significantly reduced post-harvest fruit rot compared to the control (six water sprays). Applications of fungicide only at bloom generally had higher fruit rot incidence than found for the pre-harvest and full season fungicide programs. Results indicate that pre-harvest (post-bloom) fungicide sprays are beneficial for control of post-harvest Botrytis fruit rot, especially when coupled with cold-temperature storage. Accepted for publication 8 August 2008. Published 15 October 2008.

Development of a Reduced Use Fungicide Program for Control of Botrytis Fruit Rot on Annual Winter Strawberry.

Crop phenology and epidemiological information were used to design a reduced use fungicide program for control of Botrytis fruit rot in winter annual strawberry. Fungicide spray programs during early and late periods of the season using high and low rates of captan were evaluated with or without second peak bloom applications of fenhexamid during the 1999-2000 and 2000-2001 seasons. During the early harvest period, low rates of captan were as effective as high rates for controlling Botrytis fruit rot and maintaining yield. Late in the season, treatments with fenhexamid over the peak bloom period significantly improved control of Botrytis fruit rot and increased marketable yield. Application of both captan and fenhexamid during the second peak bloom did not reduce Botrytis fruit rot incidence or improve yield compared with fenhexamid alone during this time period. Late season applications of captan may be reduced or eliminated when bloom applications of fenhexamid are being applied without affecting Botrytis fruit rot control. The study generated new recommendations for use of low-rate applications of captan during the early season and applications of fenhexamid during the second peak bloom period for winter annual strawberry production in Florida.

Uniformity of Strawberry Yield and Incidence of Botrytis Fruit Rot in an Annual Production System.

A plant yield and disease incidence uniformity trial was conducted to provide information concerning the efficiency and precision of field trials used to evaluate Botrytis fruit rot control methods on strawberry. Fruit yield and Botrytis fruit rot incidence were recorded for individual strawberry plants of cultivars Sweet Charlie and Camarosa grown in an annual production system over two growing seasons. A nested analysis of variance model was used to measure plot edge effects and to obtain variance components to describe the relationship between plot size and plot variance. Mean seasonal yield for Sweet Charlie was 599 g/plant and for Camarosa 972 g/plant. Mean seasonal fruit rot incidence was 10.3% for Sweet Charlie and 3.0% for Camarosa. Plants growing on the edge of plots next to aisles had higher yields (637 versus 577 g/plant for Sweet Charlie and 1047 versus 923 g/plant for Camarosa), but there was no edge effect for disease incidence. Smith's equation was used to determine the relationship between plot size and plot variance within mulched beds. Smith's index was relatively high for yield (0.92 and 0.95) and Botrytis fruit rot incidence (0.91 and 0.69) for Sweet Charlie and Camarosa, respectively. This suggests a relatively uniform distribution of seasonal yield and disease incidence among plants within beds. Using plot variances estimated from Smith's equation, the power of hypothesis tests to discriminate hypothetical treatment effects of different magnitudes was examined for each cultivar. Power analysis suggests that treatment effects ranging from 11.3 to 21.3% of the mean seasonal yield observed for Sweet Charlie and 8.6 to 16.5% of the mean seasonal yield observed for Camarosa can be detected with a power of 0.80 using four replicates of each treatment group and plot sizes ranging from 32 to eight plants/plot. For Botrytis fruit rot incidence, a power of 0.80 is achieved with treatment differences ranging from 24.9 to 44.1% of mean seasonal Botrytis fruit rot incidence for Sweet Charlie and from 44.1 to 64.9% of the mean observed for Camarosa using plot sizes ranging from 32 to 8 plants/plot. Before planting, the crown diameter and leaf number of transplants were recorded. There was no consistent significant correlation between any of these growth traits and seasonal yields or Botrytis fruit rot incidence. However, there was a consistent positive correlation for both cultivars between yield and crown diameter and also yield and leaf number during the months of December and January in the early part of the season (0.1513 ≤ r ≤ 0.314 for crown diameter and 0.106 ≤ r ≤ 0.264 for leaf number).

Management of Botrytis Fruit Rot in Annual Winter Strawberry Using Captan, Thiram, and Iprodione.

The management of Botrytis fruit rot on annual strawberry by fungicides was evaluated in Florida during the 1995-96, 1996-97, and 1997-98 seasons. Weekly applications of captan or thiram, bloom applications of iprodione applied twice during each of two peak flowering periods, and weekly applications of captan combined with iprodione bloom applications were evaluated. Significant treatment effects (P ≤ 0.05) on the incidence of Botrytis fruit rot were detected for the early, late, and whole-season periods each season. Weekly applications of captan or thiram controlled Botrytis fruit rot, reducing disease incidence by more than 41% compared to the untreated control. These treatments also affected marketable yield during two seasons, with a 42 to 127% increase in yield compared to the control. Weekly fungicide applications did not reduce the incidence of Botrytis fruit rot until at least the fourth week of harvest, 9 to 10 weeks after applications began. Bloom applications of iprodione alone reduced the incidence of Botrytis fruit rot during the second peak bloom period, and the reductions in incidence occurred 1 to 3 weeks after the start of bloom applications. This suggests that iprodione applications control infections at flowering or early stages of fruit development. However, early-season bloom applications did not reduce the incidence of Botrytis fruit rot. The control of Botrytis fruit rot by weekly captan applications was not improved by the addition of iprodione bloom applications. These data suggest that early-season fungicide applications for the control of Botrytis fruit rot in annual winter strawberry are of limited efficacy, and that bloom applications of Botryticides such as iprodione should be focused on the second peak bloom period.

FRUIT ROT CONTROL IN SMALL FRUIT CROPS WITH A NATURALLY-PRODUCED CHEMICAL

Restrictions on pesticide usage and the occurrence of fungicide resistant strains of postharvest pathogens have necessitated research for alternative methods of disease control. Psuedomonas cepacia was tested for control of Botrytis fruit rot in strawberry. Results of field applications of P. cepacia were variable. A compound isolated from P. cepacia, identified as pyrrolnitrin, was as effective as Benlate/captan (2,000 ppm) sprays in field applications. Postharvest pyrrolnitrin (100 ppm) dip inhibited growth of pathogens for three days at room temperature. A pyrrolnitrin dip followed by storage at 1°C for five days extended the shelf-life for another five days. Preharvest pyrrolnitrin sprays to `Bristol' black raspberry delayed rot development by 4 to 5 days. Captan (2,000 ppm) treatment provided no protection. In vitro tests showed that B. cinerea isolated from the fruit had developed resistance to captan. These results suggest that the use of a naturally-produced compound might afford another opportunity to reduce postharvest rots without the use of synthetic fungicides.

Boysenberries: Control of botrytis fruit rot by fungicides

Abstract The efficacy of fungicides and the optimum time of application were evaluated in spray programmes for control of botrytis fruit rot (caused by Botrytis cinerea Pers.: Fr.) in export boysenberries (Rubus hybrid). All fungicides tested controlled the disease, with dicarboximides (iprodione, myclozolin, procymidone, vinclozolin) and dichlofluanid being more effective than captan, thiram, or folpet. Avoiding dicarboximide sprays after 10% blossom (two applications of dicarboximide before 10% blossom), followed by folpet until mid harvest resulted in slightly more berry rot than a full dicarboximide programme (9 applications), but did not reduce marketable yield: therefore, a reduced use of dicarboximides is recommended to avoid problems associated with the resistant strains of B. cinerea identified in New Zealand. Degradation of dicarboximide residues on fruit after programmes of 9 applications followed first-order kinetics with calculated half-lives of 10–12 days for iprodione, 9 days for procymidon...

Combined Hormone-Fungicide Sprays for Control of Botrytis Fruit-Rot in Glasshouse Tomatoes

IN recent years, losses in glasshouse tomato crops caused by Botrytis cinerea Pers. have become serious in New Zealand. This is particularly true of crops treated with fruit-setting hormones, where the dead petals are retained at the calyx end as the fruit expands. These dried petals provide entry points for infection of the fruits. Heavily sporulating centres of infection thus develop early in the life of the crops, increasing the likelihood of later epiphytotic development of all phases of the disease. This is a frequent occurrence in crops treated with hormones. Some form of protection for these petals is desirable, therefore, to reduce loss of fruit and prevent early build-up of infection.