Grower Notes and Pest News
Preliminary report on the potential of Beauveria bassiana and Metarhizium anisopliae s.l. in antagonizing the charcoal rot causing fungus Macrophomina phaseolina in strawberry>
Charcoal rot, caused by Macrophomina phaseolina, is one of the important fungal diseases of strawberry in California. Macrophomina phaseolina is a soilborne fungus and has a wide host range, including alfalfa, cabbage, corn, pepper, and potato, some of which are cultivated in the strawberry production areas in California. The fungus infects the vascular system of the plant roots, obstructing the nutrient and water supply and ultimately resulting in stunted growth, wilting, and death of the plant. The fungus survives in the soil and infected plant debris as microsclerotia (resting structures made of hyphal bodies) and can persist for up to three years. Microslerotia germinate and penetrate the root system to initiate infection. Plants are more vulnerable to fungal infection when they are experiencing environmental (extreme weather or drought conditions) and physiological (heavy fruit bearing) stress.
Soil fumigation is the primary management option for addressing charcoal rot in strawberry. Crop rotation with broccoli can also reduce the risk of charcoal rot due to glucosinolates and isothiocyanates in broccoli crop residue that have fungicidal properties. Beneficial microorganisms such as Bacillus spp. and Trichoderma spp. are also considered, especially in organic strawberries, to antagonize M. phaseolina and other soilborne pathogens and provide some protection. The role of beneficial microbes in disease management or improving crop growth and health is gaining popularity in the recent years with the commercial availability of biofungicide, biostimulant, and soil amendment products. In a couple of recent strawberry field studies in Santa Maria, some of the beneficial microbial products improved fruit yield or crop health. These treatments can be administered by inoculating the transplants prior to planting, immediately after planting or periodically applying to the plants and or the soil. Adding beneficial microbes can help improve the soil microbiome especially after chemical or bio-fumigation and anaerobic soil disinfestation.
Similar to the benefits of traditionally used bacteria (e.g., Bacillus spp. and Pseudomonas spp.) and fungi (e.g., Glomus spp. and Trichoderma spp.), studies with entomopathogenic fungi such as Beauveria bassiana, Isaria fumosorosea, and Metarhizium spp. also demonstrated their role in improving water and nutrient absorption or antagonizing plant pathogens. The advantage of entomopathogenic fungi is that they are already used for arthropod pest management in multiple crops, including strawberry; now, there are the additional benefits of promoting crop growth and antagonizing plant pathogens. In light of some promising recent studies exploring these roles, a study was conducted using potted strawberry plants to evaluate the efficacy of two California isolates of Beauveria bassiana and Metarhizium anisopliae s.l. and their application strategies against M. phaseolina.
About 6 week old strawberry plants (cultivar Albion) from a strawberry field at the Shafter Research Station were transplanted into 1.6-gallon pots with Miracle-Gro All Purpose Garden Soil (0.09-0.05-0.07 N-P-K) and maintained in an outdoor environment. They were regularly watered, and their health was monitored for about 5 months prior to the commencement of the study. Conidial suspensions of the California isolates of B. bassiana and M. anisopliae s.l. were applied one week before, after, or at the time of applying microsclerotia of M. phaseolina to the potting mix. The following treatments were evaluated in the study:
- Untreated control
- Soil inoculated with M. phaseolina
- Soil inoculated with B. bassiana 1 week prior to M. phaseolina inoculation
- Soil inoculated with M. anisopliae s.l. 1 week prior to M. phaseolina inoculation
- Soil inoculated with B. bassiana at the time of M. phaseolina inoculation
- Soil inoculated with M. anisopliae s.l. at the time of M. phaseolina inoculation
- Soil inoculated with B. bassiana 1 week after to M. phaseolina inoculation
- Soil inoculated with M. anisopliae s.l. 1 week after to M. phaseolina inoculation
Entomopathogenic fungi were applied as 1X1010 viable conidia in 100 ml of 0.01% Dyne-Amic (surfactant) solution distributed around the plant base. To apply M. phaseolina, 5 grams of infested cornmeal-sand inoculum containing 2,500 CFU/gram was added to four 5 cm deep holes around the base of the plant. Each treatment had six pots each planted with a single strawberry plant representing a replication. Treatments were randomly arranged within each replication. The study was repeated once a few days after the initiation of the first experiment.
Plant health was monitored starting from the first week after the M. phaseolina inoculation and continued for seven weeks. Plant health was rated on a scale of 0 to 5 where 0=dead and 5=very healthy and the rest of the ratings in between depending on the extent of wilting. Data from both experiments were combined and analyzed by ANOVA using Statistix software and significant means were separated using LSD test. The influence of entomopathogenic fungal treatments applied at different times as well as the combined effect of different applications within each fungus were compared for seven weeks. Ratings for some plants that were scorched from hot summer temperatures and died abruptly were removed from the analyses.
Untreated control plants maintained good health throughout the observation period varying between the rating of 4.3 and 4.9. In general, plant health declined considerably from the 5th week after M. phaseolina inoculation. Plant health appeared to be slightly better in plants treated with entomopathogenic fungi, but there was no statistically significant difference in any except one instance. Plants treated with M. anisopliae one week prior to the application of M. phaseolina had a rating of 3.0 compared to 1.6 rating of plants inoculated with M. phaseolina alone.
When data from different treatments for each entomopathogenic fungus were compared, both B. bassiana and M. anisopliae s.l. appeared to reduce the wilting, but the plant health rating was not significantly different M. phaseolina treatment alone.
This is the first report of the impact of entomopathogenic fungi on M. phaseolina with some promise. Additional studies under more uniform environmental conditions and with more treatment options would shed more light on this approach of using entomopathogenic fungi against M. phaseolina. The current study evaluated single application of the entomopathogenic fungi and we plan to conduct additional studies with multiple applications.
Acknowledgements: We thank Dr. Kelly Ivors (previously at Cal Poly San Luis Obispo) for the pathogen inoculum and Dr. Stefan Jaronski, USDA-ARS, Sidney, MT for multiplying the entomopathogenic fungal inocula.
Dara, S. K. and D. Peck. 2017. Evaluating beneficial microbe-based products for their impact on strawberry plant growth, health, and fruit yield. UC ANR eJournal Strawberries and Vegetables. https://ucanr.edu/blogs/blogcore/postdetail.cfm?postnum=25122
Dara, S. K. and D. Peck. 2018. Evaluation of additive, soil amendment, and biostimulant products in Santa Maria strawberry. CAPCA Adviser, 21(5): 44-50.
Dara, S. K., S.S.R. Dara, and S. S. Dara. 2017. Impact of entomopathogenic fungi on the growth, development, and health of cabbage growing under water stress. Amer. J. Plant Sci. 8: 1224-1233. http://file.scirp.org/pdf/AJPS_2017051714172937.pdf
Dara, S. K., S. S. Dara, S.S.R. Dara, and T. Anderson. 2016. First report of three entomopathogenic fungi offering protection against the plant pathogen, Fusarium oxysporum f.sp. vasinfectum. UC ANR eJournal Strawberries and Vegetables. https://ucanr.edu/blogs/blogcore/postdetail.cfm?postnum=22199
Koike, S. T., G. T. Browne, and T. R. Gordon. 2013. UC IPM pest management guidelines: Strawberry diseases. UC ANR Publication 3468. http://ipm.ucanr.edu/PMG/r734101511.html
Partridge, D. 2003. Macrophomina phaseolina. PP728 Pathogen Profiles, Department of Plant Pathology, North Carolina State University. https://projects.ncsu.edu/cals/course/pp728/Macrophomina/macrophominia_phaseolinia.HTM
Vasebi, Y., N. Safaie, and A. Alizadeh. 2013. Biological control of soybean charcoal root rot disease using bacterial and fungal antagonists in vitro and greenhouse condition. J. Crop Prot. 2(2): 139-150.
Charcoal rot control with entomopathogenic fungi
1 week after Macrophomina inoculation
2 weeks after Macrophomina inoculation
3 weeks after Macrophomina inoculation
4 weeks after Macrophomina inoculation
5 weeks after Macrophomina inoculation
6 weeks after Macrophomina inoculation
7 weeks after Macrophomina inoculation
Data combined for each entomopathogenic fungus
Microbial and bioactive soil amendments for improving strawberry crop growth, health, and fruit yields: a 2017-2018 study>
In a continuous effort to explore the potential of additive, soil amendment, biostimulant, and other products, a new study was conducted in a conventional strawberry field at the Manzanita Berry Farms in Santa Maria. The following treatments were administered at different times, from planting till the end of production season, as requested by the manufacturer.
- Untreated control: Other than the soil incorporated fertilizers during the field preparation, no other nutrient inputs were added during the study.
- Grower standard: Transplants were dipped in Switch 62.5WG (cyprodinil+fludioxonil, at 5 oz/100 gal) before planting and a proprietary nutrient regimen that included administration of a humic acid-based product was followed.
- Innovak Global regimen: Nutrisorb-L (a blend of polyhydroxy carboxylic acids) at 28 fl oz/ac, starting 2 wk after planting and every 3 wk thereafter through drip. Packhard (carboxylic acids with calcium and boron) at 28 fl oz/ac, starting at the first fruit set (early January) and every 2 wk thereafter as a foliar spray.
- TerraVesco regimen: A microbe-rich Vermi-extract (worm extract) at 10% vol/vol as a transplant dip for 3 hours, followed by application through drip at 7.5 gal/ac after planting, and again in December, 2017 and January, 2018.
- Fertum regimen: Transplant dip in 1% vol/vol of Germinal Plus (a product from marine algae), followed by drip applications of Booster (a biostimulant and a natural organic fertilizer made from seaweed) at 0.5 gal/ac in late November and late December, 201; Silicium PK (a biostimulant and a natural organic fertilizer based on silicon enriched with phosphorus, potassium and seaweed extracts) at 0.5 gal/ac late December, 2017 and once a month starting from mid February to early July, 2018; and Foliar (a biostimulant and a natural organic fertilizer from marine algae) at 0.5 gal/ac in mid and late January.
- Shemin Garden regimen: EcoSil (a silica fertilizer) at 800 ml/ac once a month starting from early December, 2017 to May, 2018 through drip, and at 200 ml/ac in early May and June, 2018 as a foliar spray; ComCat (based on a plant extract) at 20 gr/ac and EcoFlora (a consortium of Azotobacter spp., Bacillus spp., Paenibacillus spp., Pseudomonas sp., Trichoderma spp., and Streptomyces spp.) at 12 oz/ac one week after EcoSil through drip until May, 2018 and ComCat at 10 gr/ac and EcoFlora at 12 oz/ac as a foliar spray in May and June, 2018.
- GrowCentia regimen-low: Yeti containing 1% bacterial culture (of Pseudomonas putida, Citrobacter freundii, Comamonas testosterone, and Enterobacter cloacae) and 2% alfalfa extract applied at 0.6 ml/gal through drip for 90 min weekly from the first drip application.
- GrowCentia regimen-high: Yeti at 1 ml/gal through drip for 90 min weekly from the first drip application.
- NanoChem regimen: EX10, a biodegradable fertilizer additive containing thermal polyaspartate at 1 qrt/ac through first drip after planting with follow up applications in early January (first bloom), mid February, and mid May, 2018. The active ingredient binds with cations such as ammonium, calcium, copper, iron, magnesium, manganese, potassium, and zinc and improves their availability for the plant.
- BiOWiSH regimen 1: Formula 1 at 1.33 oz/gal for transplant dip followed by 3.53 oz/ac through drip starting 2 wk after planting and every 4-5 wk thereafter.
- BiOWiSH regimen 2: Formula 1 at 1.33 oz/gal for transplant dip followed by 3.53 oz/ac as a foliar srpay starting 2 wk after planting and every 4-5 wk thereafter.
- BiOWiSH regimen 3: Formula 1 at 1.33 oz/gal for transplant dip followed by 3.53 oz/ac through drip starting 2 wk after planting alternated with a foliar spray every 4-5 wk.
- BiOWiSH regimen 4: Formula 1 at 1.33 oz/gal for transplant dip followed by BiOWiSH Crop 16-40-0, a microbial consortium (Bacillus amyloliquefaciens, B. lichenoformis, B. pumilus, and B. subtilis)at 3.53 oz/ac through drip starting 2 wk after planting and every 4-5 wk thereafter.
Each treatment contained a 165' long 5.7' wide bed and replicated four times in a randomized complete block design. A 15' long plot in the center of the bed was marked and netted for collecting yield and some other parameters that were compared. Strawberry cultivar BG 6-30214 was planted on 7 November, 2017. Other than the untreated control, all other products were administered on top of the grower standard fertility program. However, only the grower standard transplants were dipped in Switch 62.5WG before planting.
Various parameters were measured during the vegetative growth and fruit production periods to evaluate the impact of the treatments on crop growth, health, and yield. Data were analyzed using ANOVA and LSD test was used to separate significant means.
Transplant treatment (above) and drip application (below). Photos by Tamas Zold
Canopy growth: Canopy growth was observed on 11 December, 2017, 7 and 30 January, and 8 February, 2018 by measuring the size of the canopy along and across the length of the bed from 20 random plants per bed and calculating the area. Canopy size significantly (P = 0.0261) different among the treatments only on the last observation date where plants treated with EX10 and the GrowCentia product at the low concentration were larger than those in the grower standard.
Electrical conductivity and temperature of soil: From two random location on each bed, electrical conductivity (EC in dS/m) and temperature (oC) were measured about 3 inches deep from the surface on 12 and 25 January, 7 February, 19 March, 18 April, and 29 May, 2018. Only soil temperature on 25 January significantly (P = 0.0007) varied among treatments where the difference between the highest (untreated control) and the lowest (Vermi-extract) values was 0.8oC.
Dead plants: The number of dead plants represents empty spots in the bed due to the death of transplants. There were no obvious signs of disease or a particular stress factor associated with those plants except that they were randomly distributed within each bed and throughout the field. When counted on 18 April, 2018, BiOWiSH regimen 4, Fertum regimen, GrowCentia product at the high rate, and Innovak Global regimen had
Fruit diseases: Fruit harvested on 12 March, 3 and 13 April, and 17 May, 2018 from each marked plot was incubated at room temperature in dark in plastic containers and the fungal growth was rated 3 and 5 days after harvest (DAH) using a scale of 0 to 4 where 0=no fungal growth, 1=1-25%, 2=26-50%, 3=51-75%, and 4=76-100% fungal growth. Botrytis fruit rot or grey mold was predominant during the first two observation dates and the growth of other fungi (possibly Rhizopus spp.) was also seen during the last two dates. In general, fruit disease occurred at low levels throughout the observation period with
Sugar content in fruit: Sugar content was measured from two harvest-ready berries per bed on 17 May, 2018 using a handheld refractometer. Sugar content varied from 8.06 oBx (Innovak Global regimen) to 9.53 oBx (grower standard).
Fruit firmness: Fruit firmness was measured from eight randomly collected harvest-ready berries from each bed on 28 June, 2018. Firmness varied from 0.82 kgf (Fertum and Shemin Garden regimens) to 0.98 kgf (untreated control).
Fruit yield:Strawberries were harvested from 6 February to 22 June, 2018 on 36 dates. When compared to the grower standard, the marketable berry yield was 16.2, 15.1, 13.7, and 13% higher in Fertum regimen, EX10 treatment, Innovak Global regimen, and BiOWiSH regimen 4, respectively. The marketable berry yield was 9.8, 9, 7.5, and 6.8% higher in those respective treatments over the yield from untreated control.
It took 23 harvest dates in three months (from February to April, 2018) to obtain the first third of the total seasonal yield while the remaining two-thirds were obtained from seven harvest dates in May and six dates in June. Marketable fruit yield was higher than the grower standard in all treatments and higher than the untreated control in most treatments.
In general, fruit yields were higher and the pest and disease pressure was lower than usual during the study period. Aleo, a garlic oil based fungicide, at lower label rates was periodically used for disease management and bug vacuums were operated a few times against the western tarnished plant bug as a standard across all treatments.
This study evaluated some treatment regimens as recommended by the collaborating manufacturers and some of them appear to have a potential for use in strawberry production. These results help the manufacturers fine tune their recommendations for achieving better yields through additional studies.
Acknowledgments: We thank the planting and harvest crew at Manzanita Berry Farms for their help with the crop production aspects, Chris Martinez, Tamas Zold, and Maria Murrietta for their technical assistance, Sumanth Dara for statistical analysis, and the support of the industry collaborators who funded the study.
Plots in mid January
20180320 Treatment injection-Tamas Zold (2)
Measuring the canopy growth
EC and Temperature
Seasonal marketable berries 1
Seasonal marketable berries 2
Percent difference from UTC
Percent difference from GS
Number of berries per plot
Weight of a marketable berry
Percent difference from GS excluding UTC
Yield at different seasonal intervals
The western tarnished plant bug (or lygus bug) and different species of spider mites are major arthropod pests in California strawberries. While predatory mite releases are very popular for controlling spider mites in both organic and conventional fields, a significant amount of chemical pesticides are used for arthropod pest management in conventional fields. Nearly 280,000 pounds of active ingredient of at least 30 chemical and botanical pesticides were used in 2016 in California strawberries (USDA-NASS, 2016; CDPR, 2017) and malathion, bifenazate, naled, acequinocyl, and fenpropathrin were the most common of about 79,000 pounds of chemical pesticides. A uniform and thorough coverage of pesticide sprays is essential for effective pest management and also for reducing excessive pesticide use that could lead to resistance and environmental health issues (Shi et al., 2013). Evaluation of pesticide spray applications and their performance will help improve current pest management strategies in strawberry as they did in other crops (Nansen et al., 2011; Nansen et al., 2015).
Several factors such as the tractor speed, spray nozzles, spray volume, boom height, adjuvants, pressure, canopy characters, micro and macroclimatic conditions influence the spray coverage. A better understanding of these factors will help improve the pesticide use and efficacy, optimize the cost, and reduce pesticide drift and other associated risks (Nansen and Ridsdill-Smith, 2013).
A study was conducted during 2016 and 2017 to evaluate multiple spray configurations under varying weather conditions where more than 4000 data points were collected. Data for only two spray configurations, using Albuz ATR 80 Lilac and Albuz ATR 80 Green nozzles, are shown here.
Configuration 1: Albuz ATR 80 Lilac nozzles were used in 144 experimental applications delivering 32-80 gallons of spray volume per acre. Water-sensitive spray cards (TeeJet, Wheaton, IL) were clipped to the petioles of strawberry leaves in horizontal and vertical orientation (1 card per application for each orientation). They were placed in the strawberry canopy prior to spray applications and the coverage was determined based on the pattern on the cards using the SnapCard smartphone application. Data suggested that spray volume does not always translate into a good spray coverage (Fig. 1). There was a wide variation in the coverage that ranged from 0-55% at 33 gpa and 5-80% at 80 gpa suggesting the influence of other factors. Taking the operational and weather conditions into account, a multiple linear regression analysis was conducted to measure the relationship between predicted and observed spray coverage which appeared to have a linear correlation (Adjusted R2=0.27; F+52.6; P < 0.001) (Fig. 2). Wind speed, wind gust, ambient temperature, pressure, and tractor speed were used as explanatory variables in this analysis. Based on this regression model, four possible scenarios were developed with predicted spray coverage values (Table 1). A 2 mph increase in the wind speed from 6 mph to 8 mph could reduce the spray coverage from 61 to 45% when the tractor runs at 1 mph or from 30 to 13% when the tractor runs at 2 mph.
Configuration 2: Albuz ATR 80 Green nozzles were used in 276 experimental applications delivering 180-440 gallons of volume per acre. Since the droplet size from the Green nozzle is much larger than that from the Lilac nozzle, a better coverage is expected with the presumption of lesser sensitivity to environmental and operating conditions. However, data from the spray cards indicated a poor relationship between the spray volume and coverage under this configuration as well (Fig. 3). For example, both 200 and 350 gpa had a similar spray coverage. Multiple linear regression analysis, using strawberry canopy characteristics (plant height and width, dry weight, and canopy coverage), operating and weather conditions as explanatory variables, showed a significant linear correlation (Adjusted R2=0.45; F=199.5; P < 0.001) between observed and predicted spray coverages (Fig. 4). A prediction model under this configuration showed nearly 20% decline in spray coverage when the tractor speed increased from 1 to 2 mph (Table 2). Wind speed appeared to have a minimal impact, probably due to the droplet size.
This study demonstrates the importance of weather and operating conditions on spray coverage. Additional data will be collected in 2018 to expand our understanding of the factors that influence spray coverage. These studies will be useful to determine appropriate operating conditions such as the spray volume, tractor speed, and types of nozzles and identify weather conditions that are ideal to achieve good coverage. A free smartphone application is under development for the growers and PCAs to input weather and operating conditions to predict the spray coverage. This information will ultimately improve the pest control efficacy and contribute to sustainable pest management practices.
Acknowledgments: We thank the financial support of the California Strawberry Commission and the collaboration of several growers. We also thank the technical assistance of Daniel Olivier, Marianna Castiaux, and Ariel Zajdband, California Strawberry Commission and Robert Starnes, Jessie Liu, Laurie Casebier, Haleh Khodaverdi, and Isaac Corral, UC Davis.
CDPR. 2017. Summary of pesticide use report data 2016: California Department of Pesticide Regulation, p. 909.
Nansen C, Ferguson JC, Moore J, Groves L, Emery R, Garel N and Hewitt A. 2015. Optimizing pesticide spray coverage using a novel web and smartphone tool, SnapCard. Agronomy for Sustainable Development: 1-11. DOI: 10.1007/s13593-015-0309-y.
Nansen C & Ridsdill-Smith TJ (2013) The performance of insecticides – a critical review: Insecticides (ed. by S Trdan) InTech Europe, Croatia, pp. 195-232.
Nansen C, Vaughn K, Xue Y, Rush C, Workneh F, Goolsby J, Troxclair N, Anciso J, Gregory A, Holman D, Hammond A, Mirkov E, Tantravahi P and Martini X (2011) A decision-support tool to predict spray deposition of insecticides in commercial potato fields and its implications for their performance. Journal of Economic Entomology 104: 1138-1145. DOI: 10.1603/EC10452.
Shi M, Collins PJ, Ridsdill-Smith TJ, Emery RN and Renton M. 2013. Dosage consistency is the key factor in avoiding evolution of resistance to phosphine and population increase in stored-grain pests. Pest Management Science 69: 1049–1060. DOI: 10.1002/ps.3457.
USDA_NASS. 2016. Quick stats.
An update on the invasive spotted lanternfly, Lycorma delicatula: current distribution, pest detection efforts, and management strategies>
Spotted lanternfly (Lycorma delicatula) is an invasive planthopper that was first detected in Pennsylvania in September, 2014 (Dara et al., 2015) and believed to have arrived as eggs attached to stone in a shipment of stone from Asia. This pest is native to China and has been reported in some other Asian countries. Since its first occurrence in Berks County in Pennsylvania, it has now spread to 13 counties in the state and was also reported in Delaware and New York in November, 2017 and in Virginia in January, 2018.
Fruit trees (apple, apricot, cherry, peach), ornamental or woody trees (birch, lilac, maple, poplar, tree of heaven), and vines (grape) are among more than 70 species of hosts that are infested by spotted lanternfly. The tree of heaven (Ailanthus altissima) is a favorite of the spotted lanternfly. Several invasive pests such as the brown marmorated stink bug and the Asian citrus psyllid first found in late 90s in Pennsylvania and Florida, respectively, have spread to other states and are now found in California. Considering its current distribution of the spotted lanternfly in Pennsylvania and other states and its potential to spread to other states, this article provides an update on recent efforts to monitor and control this pest.
Biology and damage
Eggs are deposited in masses and covered by a waxy substance. There are four nymphal instars. Female lanternflies are larger than males. Nymphs and adults feed on the phloem and excrete large volumes of liquid. Severe feeding damage results in oozing wounds on the trunk, and wilting and death of affected branches.
Egg masses of the spotted lanternfly. Photo by Lawrence Barringer, Pennsylvania Department of Agriculture.
Fourth instar nymph of the spotted lanternfly. Photo by Lawrence Barringer, Pennsylvania Department of Agriculture.
Adult spotted lanternfly infestations. Photo by Lawrence Barringer, Pennsylvania Department of Agriculture.
White mold developing on the excretions of the spotted lanternfly. Photo by Lawrence Barringer, Pennsylvania Department of Agriculture.
Monitoring and controlling
Preventing the movement: To prevent the spread of the spotted lanternfly, carefully inspect potential sources such as woody plant debris, yard waste, plants, or other objects. Destroy or disinfest the sources as appropriate to prevent the spread of the pest.
Removal of the host: Removing tree of heaven, a favorite host of the spotted lanternfly and an invasive species of tree, can reduce the risk of pest infestation and spread. Reducing the plant stand to 15% is considered a primary strategy for preventing the spread of spotted lanternfly. The tree should be removed with its entire root system when possible. If the tree was cut, its stump should be treated with herbicides to prevent regrowth. Care should be taken while removing the tree of heaven since the toxic plant sap can cause skin irritation, headaches, nausea, and in some cases cardiac problems. Sumac and black walnut trees also look similar to the tree of heaven, but when bruised, the leaves of the latter give out a rancid peanut butter odor.
Sticky bands: The Pennsylvania Department of Agriculture placed 13 counties under quarantine and is currently providing sticky bands for volunteers participating in the monitoring program to place on trees. Sticky bands are placed around the tree trunk about 4' from the ground to trap the nymphs and adults that are moving around. While younger nymphs can be captured on less sticky bands, stickier bands are necessary to capture older nymphs and adult hoppers. Those not participating in the volunteer program can purchase sticky bands or sticky substances from commercial vendors or make their own by wrapping a tape around the trunk and applying petroleum jelly or other materials on the tape. This strategy helps to detect and trap the pest infestations. More than 1.7 million spotted lanternflies were reported to be trapped in 2017 in Pennsylvania using sticky bands.
Spotted lanternfly nymphs and some adults trapped on a sticky band. Photo by Lawrence Barringer, Pennsylvania Department of Agriculture.
Pesticides: Contact insecticides, bifenthrin and carbaryl and systemic insecticides, dinotefuran and imidacloprid appear to be effective in controlling the spotted lanternfly based on the studies conducted in Pennsylvania. Neem oil and insecticidal soap also provide some control. However, pesticide applications appear to be a short-term solution as they cannot prevent reinfestation.
Biocontrol agents:It is thought that toxic metabolites in the body of the spotted lanternfly and its brightly colored hindwings tend to deter general predators from feeding on the pest. However, the predatory wheel bug, Arilus cristatus (Hemiptera: Reduvidae) and stink bug, Apoecilus cynicus were found feeding on adult spotted lanternfles in Pennsylvania (Barringer and Smyers, 2016). Some egg parasitoids were also reported to be attacking the spotted lanternfly in China (Choi et al., 2014) and South Korea (Kim et al., 2011). Liu and Mottern (2017) found Ooencyrtus kuvanae, an egg parasitoid imported for controlling the gypsy moth (Lymantria dispar), attacking the egg masses of the spotted lanternfly in Pennsylvania in 2016. These native predators and introduced parasitoids could be potential biocontrol options for the spotted lanterfly.
Microbial control agents: Entomopathogenic fungi Beauveria bassiana, Isaria fumosorosea, and Metarhizium brunneum may also play a role alone or in combination with azadirachtin for controlling spotted lanternfly and researchers should explore microbial control.
Refer to the earlier article on the pest biology and damage at //ucanr.edu/blogs/blogcore/postdetail.cfm?postnum=15861
Spotted lanternfly in Entomology Today: https://entomologytoday.org/2015/12/17/be-prepared-for-spotted-lanternfly/
Barringer, L. E. and E. Smyers. 2016. Predation of the spotted lanternfly, Lycorma delicatula (White) (Hemiptera: Fulgoridae) by two native hemiptera. Entomol. News 126: 71-73. https://doi.org/10.3157/021.126.0109
Choi, M. Y., Z.Q. Yang, X. Y. Wang, Y. L. Tang, and Z. R. Hou. 2014. Parasitism rate of egg parasitoid Anastatus orientalis (Hymenoptera: Eupelmidae) on Lycorma delicatula (Hemiptera: Fulgoridae) in China. Korean J. Appl. Entomol. 53: 135–139.
Dara, S. K., L. Barringer, and S. P. Arthurs. 2015. Lycorma delicatula (Hemiptera: Fulgoridae): A new invasive pest in the United States. J. Integ. Pest Mngmt. 6(1): 20. https://doi.org/10.1093/jipm/pmv021
Kim, I. K., S. H. Koh, J. S. Lee, W. I. Choi, and S. C. Shin. 2011b. Discovery of an egg parasitoid of Lycorma delicatula (Hemiptera: Fulgoridae) an invasive species in South Korea. J. Asia Pac. Entomol. 14: 213–215.
Liu H. and J. Mottern. 2017. An old remedy for a new problem? Identification of Ooencyrtus kuvanae (Hymenoptera: Encyrtidae), and egg parasitoid of Lycorma delicatula (Hemiptera: Fulgoridae) in North America. J. Ins. Sci. 17: 1-6. https://doi.org/10.1093/jisesa/iew114
The biopesticides market has been experiencing a rapid growth in recent years; however, plant- and microorganism-based biopesticides have been used for centuries for controlling pests. According to 17th century records, plant extracts such as nicotine were some of the earliest agricultural biopesticides used to control plum beetles and other pests (BPIA, 2017). Experimentation involving biological controls against lepidopteran pests were performed as early as 1835, during Agostine Bassi's efficacy demonstrations of the white muscardine disease caused by a fungus now known as Beauveria bassiana against lepidopteran pests (BPIA, 2017). Further, the use of mineral oils as plant protectants was cited in experiments during the 19th century (BPIA, 2017).
In the early 20th century, an increasing number of studies involving biopesticides emerged during the rapid institutional expansion of agricultural research (Stoytcheva, 2011). The bacterium Bacillus thuringiensis (Bt) was the initial biopesticide and has the most widespread use to this day. In 1901, Bt was isolated from a diseased silkworm by Japanese biologist Shigetane Ishiwata. Ten years later, German researcher Ernst Berliner rediscovered it in a diseased flour moth caterpillar (BPIA, 2017). Other commercial success stories from the 1980s and 1990s involve the use of Agrobacterium radiobacter to prevent crown gall on woody crops (Escobar and Dandekar, 2003) as well as utilizing Pseudomonas fluorescens for the prevention of fire blight in orchards with streptomycin-resistant pathogen populations (Stockwell et al., 2010).
Resurgence in academic and industrial research for biopesticide development occurred in response to rising costs associated with the overuse of synthetic chemicals. Increasing biopesticide adoption has resulted, in part due to rapid expansion of organic agriculture during the past decade (Eze et al., 2016). As a result, the development of new biopesticides has continued to increase since the mid-1990s. Over 100 active ingredients have been registered with the United States Environmental Protection Agency (USEPA) Biopesticides Division since 1995 (EPA, 2017). The increasing cost of developing chemical pesticides (Fig. 1) could also have contributed to the rise in biopesticide registration (McDougall, 2016).
Fig. 1. Costs to discover and develop a synthetic agricultural chemical. (Based on McDougall 2016)
Biopesticides currently represent approximately 5% of the total pesticide market (Olson, 2015). However, the biopesticides market is experiencing rapid growth of about three times the rate associated with conventional agricultural chemicals (Chandler et al., 2011). The trend toward the use of biopesticides is growing stronger for two major reasons; the first is the fact that biologicals alone and in combination with chemicals have the potential to provide superior yields and quality (Yadav et al., 2013; Dara, 2015 & 2016; BPIA, 2017;). Secondly, increasing regulatory restriction on chemicals has established restrictive barriers to bringing new products to market while countries such as Europe simultaneously are eliminating pesticide active ingredients at a rapid rate (Erbach, 2012) (Fig. 2).
Fig.2. Numbers of new agricultural chemical leads and launches from 1995-2010 (Based on data from Ag Chem New Compound Review, 2010).
Over 200 biopesticide products are currently sold in the US, in comparison to only 60 comparable products in the European Union. Overall, more than 225 microbial biopesticides are presently manufactured within 30 countries that belong to the Organization for Economic Cooperation and Development. Approximately 45% of the total biopesticide use occurs in USA, Canada, and Mexico, whereas Asia uses around 5% of biopesticides sold globally (Kumar & Singh, 2016).
According to Berkshire Hathaway, the global biopesticides market is projected to reach a value of $8.8 billion by 2022, representing annual average growth of 17% from 2016 (Brzoskiewicz, 2018). Primary growth factors affecting the biopesticides market include growth in crop production, ease of application, increase the in need for organic food, and growing preference for sustainable pest control methods. Although biopesticides currently account for approximately 2% of the plant protectants used globally, the growth rate indicates an increasing trend during the past two decades, wherein the global use of biopesticides is increasing steadily by 10% every year (Brzoskiewicz, 2018).
Biostimulants are a recent emergent area within which functionality and regulatory guidelines may not be as well-defined as those for biopesticides. A plant biostimulant is defined as “any substance or microorganism applied to plants with the aim to enhance nutrition efficiency, abiotic stress tolerance and/or crop quality traits, regardless of its nutrients content” (du Jardin, 2015, p. 3). Chatzikonstantinou (2017) regarded fertilizers and biostimulants as being a part of the same family, with reasoning based in their similarities for helping plants to simulate nutrients, boosting tolerance to abiotic stress factors, and increasing the quality of crops. There are currently no federal statutory definitions for biostimulants in the US, and uncertainty exists in both federal and state regulatory agencies in terms of how to develop guidelines for plant biostimulant categories (Russell, 2015).
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