Integrated Management Programs Research Articles

A Study on the Toxicity and Sublethal Concentrations of Three Insecticides on the Population Dynamics of Green Lacewing Chrysoperla carnea Stephens

Alsendi, A., A.A. Kareem, M. Havasi and Gh. Golmohammadi. 2023. A Study on the Toxicity and Sublethal Concentrations of Three Insecticides on the Population Dynamics of Green Lacewing Chrysoperla carnea Stephens. Arab Journal of Plant Protection, 41(1): 28-36. https://doi.org/10.22268/AJPP-41.1.028036 The study was carried out to evaluate toxicity and sublethal effects of lufenuron, novaluron, and lambda-cyhalothrin on natural enemies such as Chrysoperla carnea. All sub-lethal concentrations caused a significant decrease in oviposition period, total fecundity, longevity, and total life span of C. carnea compared to the control. Maximum and minimum mean lifespan of C. carnea individuals were observed in the untreated group and LC30 concentration of novaluron. Total fecundity varied from 153.47 offspring/individual in treatment with LC30 novaluron to 300.12 offspring/individual in the control treatment. The highest value for intrinsic and finite rate of increase (r, λ) was obtained by the concentration of lambda-cyhalothrin. The net reproduction rate (R0) reached its lowest level in novaluron treatment. As a result, the effects of sublethal concentrations of lufenuron, novaluron, and lambda-cyhalothrin on C. carnea were assessed and discussed to design improved integrated management programs. Keywords: Integrated pest management, side effects, aphidophagous predators, natural enemies.

Behavioural Response of Whitefly Bemisia tabaci (Hemiptera: Aleyrodidae) Towards Volatile Organic Compounds Emitted from Eggplant Leaves

The whitefly Bemisia tabaci is considered one of the most destructive insect pests that can attack several vegetable crops worldwide. The behavior of choosing a host plant by whitefly can be significantly influenced by volatile organic compounds. The aim of this investigation is to identify and bioassay the volatile organic compounds emitted from uninfested and infested eggplant leaves with B. tabaci. The current study focuses on the interaction between whitefly and eggplant with the identification of volatile organic compounds emitted from leaves that were collected by headspace solid phase microextraction fiber and gas chromatography mass spectrum analyzed. Both uninfested and infested eggplant leaves released a total of 11 compounds. The amount of volatile organic compounds emitted from affected eggplant leaves by whitefly was higher than from uninfested eggplant leaves. Using a Y-shaped olfactometer bioassay, whitefly preferred to attract toward volatile emitted by eggplant leaves in both uninfested and infested eggplant leaves. Our results suggest these chemical compounds can play a key mediator in host finding behavior. The exploitation of one or more of these compounds can apply in an integrated management program of this pest as a lure in the sticky trap or manipulating insect behavior.

Diverse environmental bacteria displaying activity against Phakopsora pachyrhizi, the cause of soybean rust.

The management of soybean rust (SBR) caused by the obligate fungus Phakopsora pachyrhizi mostly relies on the use of synthetic fungicides, especially in areas where the disease inflicts serious yield losses. The reliance on synthetic fungicides to manage this disease has resulted in resistance of P. pachyrhizi populations to most fungicides. In this study, bacteria isolated from diverse environments were evaluated for their biocontrol potential against P. pachyrhizi using soybean detached-leaf method and on-plant in the growth chamber, greenhouse, and field. Among 998 bacterial isolates evaluated using the detached-leaf method; 58% were isolated from plant-related materials, 27% from soil, 10% from insects, and 5% from other environments. Of the isolates screened, 73 were active (they had ⪖ 75% rust reduction) with an active rate of 7.3%. From the active isolates, 65 isolates were re-tested on-plant in the growth chamber for activity confirmation. In the confirmation test, 49 bacteria isolated from plant-related materials maintained their activity with a confirmation rate of 75%. The majority of bacteria with confirmed activity belonged to the taxonomic classes Bacilli and Gammaproteobacteria (70%). Active isolates were prioritized for greenhouse and field testing based on activity in the initial screen and confirmation test. Six bacterial isolates AFS000009 (Pseudomonas_E chlororaphis), AFS032321 (Bacillus subtilis), AFS042929 (Bacillus_C megaterium), AFS065981 (Bacillus_X simplex_A), AFS090698 (Bacillus_A thuringiensis_S), and AFS097295 (Bacillus_A toyonensis) were selected from those bacteria that maintained activity in the confirmation test and were evaluated in the greenhouse, and five among them were evaluated in the field. From the Alabama field evaluation, all bacterial isolates reduced rust infection as well as azoxystrobin (Quadris® at 0.3 L/ha) used as the fungicide control (P > 0.05). Moreover, the scanning electron micrographs demonstrated evidence of antagonistic activity of AFS000009 and AFS032321 against P. pachyrhizi urediniospores. Bacterial isolates that consistently showed activity comparable to that of azoxystrobin can be improved through fermentation and formulation optimization, developed, and deployed. These bacteria strains would provide a valuable alternative to the synthetic fungicides and could play a useful role in integrated disease management programs for this disease.

Overcoming Barriers to the Implementation of Integrated Musculoskeletal Pain Management Programs: A Multi-Stakeholder Qualitative Study

Integrated pain management (IPM) programs can help to reduce the substantial population health burden of musculoskeletal pain, but are poorly implemented. Lessons learned from existing programs can inform efforts to expand IPM implementation. This qualitative study describes how health care systems, payers, providers, health policy researchers, and other stakeholders are overcoming barriers to developing and sustaining IPM programs in real-world settings. Primary data were collected February 2020 through September 2021 from a multi-sector expert panel of 25 stakeholders, 53 expert interviews representing 30 distinct IPM programs across the United States, and 4 original case studies of exemplar IPM programs. We use a consensual team-based approach to systematically analyze qualitative findings. We identified 4 major themes around challenges and potential solutions for implementing IPM programs: navigating coverage, payment, and reimbursement; enacting organizational change; making a business case to stakeholders; and overcoming regulatory hurdles. Strategies to address payment challenges included use of group visits, linked visits between billable and nonbillable providers, and development of value-based payment models. Organizational change strategies included engagement of clinical and administrative champions and co-location of services. Business case strategies involved demonstrating the ability to initially break even and potential to reduce downstream costs, while improving nonfinancial outcomes like patient satisfaction and provider burnout. Regulatory hurdles were overcome with innovative credentialing methods by leveraging available waivers and managed care contracting to expand access to IPM services. Lessons from existing programs provide direction on to grow and support such IPM delivery models across a variety of settings. PerspectiveIntegrated pain management (IPM) programs face numerous implementation challenges related to payment, organizational change, care coordination, and regulatory requirements. Drawing on real-world experiences of existing programs and from diverse IPM stakeholders, we outline actionable strategies that health care systems, providers, and payers can use to expand implementation of these programs.

Commercial Hard Squash Cultivars Exhibit Differences in Susceptibility to Phytophthora Crown Rot

Crown rot and fruit rot, caused by the oomycete Phytophthora capsici, limit the yield and quality of hard squash grown for processing. In a 2-year field study, we compared four Butternut types ( Cucurbita moschata), two Delicious varietal Hubbard types ( Cucurbita maxima), and six Kabocha types ( C. maxima) for crown rot resistance and fruit characteristics relevant to processing including mesocarp soluble solids, percentage of dry matter, and average fruit weight in 2019 and 2020. To evaluate crown rot, plants were inoculated in replicated field trials. The C. moschata cultivars Dickinson, Buckskin, New England Cheddar, and Ultra Butternut had significantly less plant death in both years (<15%) than other cultivars. Significantly fewer Thunder plants died in 2020 (59.6%) compared with the Kabocha cultivars Sweet Mama (>94.2%), Delica (≥92.3%), and Sunshine (≥90.4%) and had a lower relative area under the disease progress curve value (≤22.4) in both years. In noninoculated field trials, mature fruits were assessed for fruit characteristics. Of the resistant C. moschata cultivars, only Ultra Butternut exhibited similar °Brix to NK 580 in both years and had comparable or greater dry matter and fruit weight. Kabocha cultivars with moderate crown rot susceptibility (i.e., Thunder) exhibited higher °Brix and dry matter and smaller fruit weight compared with NK 580 each year. Integrated management programs can be advanced by selecting cultivars with crown rot resistance. Further evaluation of desirable yield and quality characteristics of the resistant cultivars could accelerate acceptance of these cultivars by growers and processors.

Diaspis echinocacti (Hemiptera: Diaspididae) on cactus pear cladodes: biological aspects at different temperatures.

The scale mealybug, Diaspis echinocacti (Bouché, 1833) (Hemiptera: Diaspididae), is one of the main pests of the cactus pear in Brazil. The objective was to study biological aspects of D. echinocacti at the constant temperatures of 25, 28, 30, 33 and 35 °C with relative humidity of 60 ± 10% and photoperiod of 12 hours in the laboratory on the cactus pear cultivar, "Orelha de Elefante Mexicana", Opuntia stricta [Haw.] Haw. The development period (22 to 35 days) and survival in the egg (92 to 100%) and nymph (21.8 to 100%) stages and of the egg-adult cycle (20 to 100%), longevity (34.1 to 59.6 days) and fecundity (33 to 112 eggs) of D. echinocacti females with the different temperature and absence of males at the highest temperatures (> 30°C), indicated that the range between 25 °C and 30°C is the most favorable for this scale mealybug. This information may help to improve integrated management programs for D. echinocacti, in areas subject to seasonal temperature changes in the Brazilian regions where cactus pear is cultivated.

Citrus Canker Pathogen, Its Mechanism of Infection, Eradication, and Impacts

Citrus canker is a ravaging bacterial disease threatening citrus crops. Its major types are Asiatic Canker, Cancrosis B, and Cancrosis C, caused by Xanthomonas citri pv. citri (Xcc), Xanthomonas citri pv. aurantifolii pathotype-B (XauB), and pathotype-C (XauC), respectively. The bacterium enters its host through stomata and wounds, from which it invades the intercellular spaces in the apoplast. It produces erumpent corky necrotic lesions often surrounded by a chlorotic halo on the leaves, young stems, and fruits, which causes dark spots, defoliation, reduced photosynthetic rate, rupture of leaf epidermis, dieback, and premature fruit drop in severe cases. Its main pathogenicity determinant gene is pthA, whose variants are present in all citrus canker-causing pathogens. Countries where citrus canker is not endemic adopt different methods to prevent the introduction of the pathogen into the region, eradicate the pathogen, and minimize its dissemination, whereas endemic regions require an integrated management program to control the disease. The main aim of the present manuscript is to shed light on the pathogen profile, its mechanism of infection, and fruitful strategies for disease management. Although an adequate method to completely eradicate citrus canker has not been introduced so far, many new methods are under research to abate the disease.

Phymatotrichopsis root rot and its biological control in the pecan tree in Mexico

In Mexico, phymatotrichopsis root rot is regarded as the most important disease in the pecan tree. Its causative agent is the fungus Phymatotrichopsis omnivora (Duggar) Hennebert, and the percentage of diseased trees ranges between 3 to more than 25% in a plantation. Symptoms vary from mild damages to the death of the infected tree. The roots invaded by the fungus die with the consequent reduction of the foliage. Chemical control is one of the most used methods to control this pathogenic fungus, but it is expensive and not very efficient, so it is necessary to try other methods such as antagonistic fungi, resistant varieties, plant extracts, among others that have been shown to have some effectiveness, and to design an integrated management program for the pest. For all the reasons stated, the objective of this review was to address the most current aspects of the disease and its biocontrol in Mexico.

Foliar spraying of elicitors in pear trees induced resistance to Cacopsylla bidens

• Elicitors influence the Cacopsylla pyricola population. • Chitosan induced resistance to Cacopsylla pyricola. • Chitosan for IPM of Cacopsylla pyricola. • Activity of detoxifying enzymes in pear psyllid is altered by elicitor application. • Elicitors influence secondary metabolites. The pear psylla, Cacopsylla pyricola is a serious pest of pear worldwide. In this research, the effects of salicylic acid (SA), chitosan, γ-aminobutyric acid (GABA), and Serenade Aso ( Bacillus subtilis QST713) were studied on the induced resistance of pear trees to C. pyricola . The treatments showed a significant difference in terms of population growth of C. pyricola after 7 and 14 days during two years. In 2019, the mean population growth of total life stages of C. pyricola in the studied treatments was significantly lower than control after 7 and 14 days of spraying. In 2020 (7 and 14 days after spraying), the percent decline in the mean population of pear psylla (total life stages) was highest on chitosan treatment (75 and 85 %, respectively) and the lowest on control (30 and 48 %, respectively). GC-MS analysis revealed the range of chemicals in the pear leaves under different treatments. Based on the results, 23 compounds were identified, including 9 alkaloids, 6 flavonoids, 4 polyphenols, 3 terpenoids, and one glycoside. In all treatments except Serenade, the amounts of alkaloids increased compared to the control. Furthermore, the activity of catalase and glutathione S- transferase enzymes in C. pyricola under chitosan treatment was significantly higher than others; but the activity of peroxidase significantly decreased on chitosan compared to SA and GABA. The lower levels of peroxidase in C. pyricola reared on trees treated with chitosan indicate this insect has not been able to detoxify plant secondary metabolites effectually. In addition, our findings suggested that chitosan on pear trees could act effectively in reducing the C. pyricola population and can be considered in integrated management programs of this pest.

Predicting common bean (Phaseolus vulgaris) productivity according to Rhizoctonia root and stem rot and weed development at field plot scale.

A two-year research trial was conducted to evaluate progression of common bean (Phaseolus vulgaris) growth, Rhizoctonia root rot and weed development in association with productivity when treated with different cultivars, planting dates and weed control methods in north-western part of Iran. To determine the best descriptors, six standard curves were examined to model development of bean dry matter, Rhizoctonia root rot incidence, and weed density during two growing seasons across 256 field plots. Exponential and linear-by-linear models were fitted to bean-disease-weed progression data, and then model parameters representing over-season progress curve elements were used in multivariate regression analyses to estimate bean production. Furthermore, using herbicides (Imazethapyr and Trifluralin) restricted weed density by 28% in early (mid-spring) and 42% in late (late spring to early summer) plantings. Late plantings of two bean cultivars decreased disease progress up to 36% for herbicide use, hand-weeding and control. Although bean dry matter, pod and seed production for herbicide use and hand-weeding treatments were 6-17% greater than control, late planting improved productivity in control by 10-24%. Findings suggested that late planting of bean improved efficiency of herbicides to control weeds. Late planting also restricted Rhizoctonia root rot progress and thus, improved bean yield. There were significant correlations between bean-disease-weed development descriptors. According to principal component analysis, bean-disease-productivity-weed variables accounted for 80% of total data variance. Such information extends our understanding of bean-disease-weed progress in interaction with planting date to develop more effective and sustainable integrated Rhizoctonia management programs.

Genetic parameters for resistance to gastrointestinal nematodes in sheep: a meta-analysis

Gastrointestinal nematodes (GINs) are damaging parasites of global sheep populations. The key weapons in fighting GINs have been anthelmintic drugs, but the emergence of drug-resistant parasites has meant that alternative control methods are needed. One of these alternatives is to breed for enhanced host resistance to GINs, and decades of research have estimated the genetic contribution to different measures of resistance to GINs and their genetic correlations with other desirable performance traits. It is clear that parasite resistance is a heritable trait that can be selected for. Despite this consensus, estimates of both heritability of resistance and genetic correlations with other traits vary widely between studies, and the reasons for this variation have not been examined. This study provides a comprehensive and quantitative meta-analysis of genetic parameters for resistance to GINs in sheep, including measures of worm burden (faecal egg counts, FECs), anti-parasite immunity (GIN-specific antibodies), and parasite-induced pathology (FAMACHA© scores). Analysis of 591 heritability estimates from 121 studies revealed a global heritability estimate for resistance to GINs of 0.25 (95% confidence interval (CI) = 0.22–0.27) that was stable across breeds, ages, geographical location and analytical methods. Meanwhile, analysis of 559 genetic correlations from 54 studies revealed that resistance to GINs overall has a positive genetic correlation of +0.10 (95% CI = 0.02–0.19) with performance traits, and that this was consistent across breeds, ages, sexes and analytical methods. Importantly, the direction of the genetic correlation varied with the resistance trait measured: while FECs and FAMACHA© scores were favourably correlated with performance traits, adaptive immune markers were unfavourably correlated, suggesting that selection for enhanced immune responses to GINs could reduce animal performance. Overall, the results suggest that breeding for resistance to GINs should continue to form part of integrated management programs to reduce the impact of parasites on health and performance, but that selection for enhanced immune responses should be avoided.

Micronutrients Foliar and Drench Application Mitigate Mango Sudden Decline Disorder and Impact Fruit Yield

Mango sudden death (MSD) or quick decline (QD) is the most destructive disease found in mango orchards of Pakistan and is characterized by collapse of the vascular system by Ceratocystis fimbriata and Lasiodiplodia theobromae. Cultural practices, chemicals, and biological control are the most valuable tools for the management of MSD, but the role of micronutrient deficiencies has remained an area that is heavily ignored by the farming community. To study the impact of micronutrients, four mango orchards were selected at different locations where different combinations of micronutrients, i.e., Zinc (Zn), Boran (B), and Copper (Cu) in the form of Zinc sulphate (ZnSO4), Borax/Boric acid (H3BO3), and Copper Sulphate (CuSO4), were applied both foliar and in drench along with the recommended doses of Nitrogen: Phosphorous: Potassium (NPK), and Farmyard manure (FYM), respectively. The quantities of micronutrients were determined from the soil and leaves before and after application of the treatments. The impact of micronutrients was measured in terms of reduction in disease severity and increase in fruit yield. The results revealed that the application of all three micronutrients both in soil drench and in foliar form significantly decreased the disease severity at three locations and increased the yield in all four mango orchards. Application of ZnSO4 (0.8%), +H3BO3 (0.8%), +CuSO4 (0.5%) and as soil drench ZnSO4 (400 g) + Borax (200 g) + CuSO4 200 g plant−1 proved to be the best treatments, with an average of 12.88 and 14.03% reduction in disease severity and with an average yield of 128 and 119 kg, respectively. The application of micronutrients would be a promising solution in an integrated disease management program used to tackle MSD.

Efficacy of Genetic Resistance and Fungicide Application Against Fusarium Head Blight and Mycotoxins in Wheat Under Persistent Pre- and Postanthesis Moisture.

Field experiments were conducted to investigate the efficacy of fungicide treatments in combination with genetic resistance against Fusarium head blight (FHB) and its associated mycotoxins under persistently wet pre- and postanthesis conditions in plots inoculated with Fusarium graminearum-colonized corn spawn. Treatments consisted of a single application of prothioconazole + tebuconazole at early anthesis (PA), or at 3 (P3), 6 (P6), or 9 (P9) days after early anthesis, or PA followed by a single application of metconazole at 3 (PA+C3), 6 (PA+C6), or 9 (PA+C9) days after early anthesis. PA and P3 were the most efficacious of the single-application treatments in terms of mean percentage control of FHB index (IND), deoxynivalenol (DON), zearalenone (ZEA), and mean increase in grain yield and test weight (TW) relative to the nontreated susceptible check (S_CK). The double-application treatments (PA+C3, PA+C6, and PA+C9) were the most effective of all tested fungicide programs. However, relative to S_CK, the highest overall mean percentage reduction in IND, DON, and ZEA and increase in grain yield and TW were observed when the double-application fungicide programs were integrated with genetic resistance. The estimated net cash income (NCI) of the integrated management (IM) programs was consistently higher than the NCI of other tested programs across different grain prices and fungicide application costs. Thus, the benefits of the two-treatment IM programs under highly favorable conditions for FHB development were enough to offset the cost of two applications, making these programs profitable.

Field applications of granular and liquid pyrethroids, carbaryl, and IGRs to control the asian longhorned tick (Haemaphysalis longicornis) and impacts on nontarget invertebrates

Few documented control strategies exist for the invasive tick, Haemaphysalis longicornis, despite its potential to reach extremely high numbers and vector human and animal pathogens. In 2020, we evaluated the effects of single applications of five granular and liquid acaricides on H. longicornis in a public park in northern New Jersey. Acaricides tested included pyrethroids (lambda-cyhalothrin, bifenthrin), a carbamate (carbaryl), and the insect growth regulators (IGRs) pyriproxyfen and novaluron. We also monitored the impact of each treatment on non-target soil and above-ground invertebrate species using pitfall and sticky traps, respectively. We recorded over 70,000 H. longicornis ticks in the study area from July to October 2020. An average of 99% control was achieved with lambda-cyhalothrin spray and 95% with granular bifenthrin. In contrast, granular carbaryl did not significantly reduce any life stages of H. longicornis. The IGR (pyriproxyfen/novaluron) resulted in a significant 45% reduction of the larval stage following treatments in July. No other stages were significantly impacted by pyriproxyfen alone or in combination with novaluron. Analysis of non-target species revealed that the community composition of soil-dwelling arthropods was strongly impacted by pyrethroid treatments and, to a lesser extent, by the carbamate treatment. The granular pyrethroid bifenthrin had more pronounced effects and impacted a broader range of non-target groups in the pitfall traps than the liquid pyrethroid lambda-cyhalothrin. Arthropod groups that were negatively impacted included Isopoda, Formicidae, Coleoptera, Araneae, Acari, and Grylloidea. Collembola numbers, however, were elevated in both pyrethroid treatments. The community composition of arthropods collected on the above-ground sticky traps was strongly impacted only in the liquid lambda-cyhalothrin treatment. The primary groups impacted in the sticky trap analysis were Collembola and Hemiptera. Community composition in traps remained distinct in the pyrethroid treatments through the entire survey period up to 62 days post-treatment. The results of this study indicate that pyrethroid acaricides were highly effective at controlling H. longicornis, while other compounds, including carbaryl and IGRs, did not achieve consistent levels of control. Further research is needed to find effective and environmentally sustainable alternatives. Integrated management programs can include the judicious use of pyrethroids to control H. longicornis.

Physicochemical Properties of Sugarcane Cultivars Affected Life History and Population Growth Parameters of Sesamia nonagrioides (Lefebvre) (Lepidoptera: Noctuidae).

Simple SummaryThe sugarcane stem borer, Sesamia nonagrioides (Lefebvre), is the most important pest of sugarcane in Iran and some other regions of the world. Variation in the resistance of six commercial sugarcane cultivars to S. nonagrioides was investigated using the oviposition preference, life history, and population growth parameters. Moreover, the physical and biochemical properties of the tested sugarcane cultivars were estimated to understand any possible correlation between the insect’s parameters and the physiochemical features of the cultivars tested. The physicochemical properties of sugarcane cultivars significantly affected S. nonagrioides oviposition behavior, life history, and population parameters. Based on the obtained results, the resistant cultivar, SP70-1143, could be recommended for cultivation in sugarcane fields where the risk of S. nonagrioides damage is usually high.The use of resistant cultivars is an efficient management strategy against S. nonagrioides. The effects of different sugarcane cultivars, CP48-103, CP57-614, CP69-1062, CP73-21, SP70-1143, and IRC99-02 were evaluated on the oviposition preference (free-choice assay), life history, and life table parameters of S. nonagrioides at 27 ± 1 °C, 60 ± 5% RH and a photoperiod of 16: 8 (L: D) h. The longest and shortest developmental times were on cultivars SP70-1143 and CP48-103, respectively. The oviposition preference of S. nonagrioides was the highest on cultivars CP48-103 and CP69-1062, and negatively correlated with the shoot trichome density and shoot rind hardness of the cultivars. The highest intrinsic rate of increase of S. nonagrioides was on cultivar CP48-103 and the lowest was on cultivar SP70-1143. The shortest mean generation time was on CP48-103 and the longest was on SP70-1143. The results indicate that cultivars CP48-103 and CP69-1062 were susceptible, and cultivar SP70-1143 was partially resistant against S. nonagrioides. This information could be useful for developing integrated management programs of S. nonagrioides, such as the use of resistant cultivars to reduce the damage caused by this pest in sugarcane fields.

The predation impact of ruby-throated hummingbird, Archilochus colubris, on spotted-wing drosophila, Drosophila suzukii, in raspberry, Rubus idaeus

Hummingbirds require arthropods in their diet and may consume 2000 small insects per day, including drosophilids, when nesting. In New York, we investigated the use of feeders to attract Ruby-throated Hummingbirds, Archilochus colubris (Linnaeus, 1758), into red raspberry, Rubus idaeus L., to encourage predation of the spotted-wing drosophila, Drosophila suzukii Matsumura. We investigated whether fly populations and fruit infestation would be reduced in the half of the field with feeders compared to the half without. Over four years, 2015–2018, 81% of 266 hourly observations of hummingbird behavior found they were occupying the field when utilizing the feeders, supporting opportunities for predation on D. suzukii. In 2016 to 2018, when maximal hummingbird sightings were reached, significant reductions in D. suzukii trap counts and fruit infestation levels were obtained in some weeks in the half of the field provided with feeders at a density of 62 feeders/hectare. Compared to the half without feeders, the final tally of cumulative trap counts and fruit infestation levels were lower in the half of the field treated with feeders in all years. In comparing two paired commercial raspberry fields (in 2020), one with feeders at a density of 151 feeders/hectare and the other without feeders, presence of feeders significantly reduced trap counts in most weeks during the fruiting season. No Ruby-throated Hummingbirds were observed in the commercial field without feeders. Hummingbirds may protect fruit from D. suzukii when they are encouraged with feeders to visit and occupy raspberry plantings. The presence of hummingbirds in raspberry fields has the potential to contribute to a D. suzukii integrated management program and reduce the reliance on pesticides.

Epiphytic yeasts as potential antagonists against Fusarium head blight of wheat (Triticum aestivum L.) caused by Fusarium graminearum sensu stricto

Fusarium head blight (FHB), caused by Fusarium graminearum , is a significant disease of wheat in all wheat-growing areas. In this study, we screened a total of 344 yeast epiphytes isolated from cereal and weed plants against F. graminearum in vitro . Twelve potential antagonists were selected and subjected to in planta screening trials. In the in vitro bioassay trials, the highest average percentage inhibition of 64.31% (Isolate MGO2) was observed. The in vivo evaluation of the best 12 isolates showed a reduction in FHB severity and deoxynivalenol (DON) concentration of up to 15.62% (Isolate WL3) and 28.96% (Isolate SCH7), respectively. We observed a positive correlation between Area Under the Disease Progress Curve (AUDPC) and percentage seed infection. The 100-seed weight, however, was negatively correlated to both the AUDPC and the percentage seed infection. The best three yeast antagonists were selected based on AUDPC units, percentage seed infection, and 100-seed weight parameters and were identified as Papiliotrema flavescens (Isolates WL3 and WL6) and Pseudozyma sp. (Isolate MGO1) using 16S rRNA sequence analysis. These three yeast antagonists showed biocontrol efficacy against F . graminearum, and their incorporation in an integrated management programme could provide enhanced FHB control. To the best of our knowledge, this is the first report of yeast epiphytes isolated from Panicum maximum, and Ophiopogon japonicus tested as potential biological control agents against F. graminearum.

Agronomic cover crop management supports weed suppression and competition in California orchards

AbstractCover crops enhance the biodiversity of cropping systems and can support a variety of useful ecosystem services, including weed suppression. In California orchards, cover crops are typically implemented as annual plants that can replace resident vegetation in orchard alleyways during the rainy winter season. Our research objective was to evaluate cover crop management factors that support a competitive, weed-suppressing cover crop in the unique orchard systems of central California. We conducted two experiments: an experiment evaluating cover crop management intensification in walnuts (Juglans regia L.) and an experiment evaluating multispecies cover crop mixes and planting date in almonds [Prunus dulcis (Mill.) D.A. Webb]. These experiments demonstrate that timely cover crop planting is important for producing an abundant cover crop, and a variety of cover crop management programs can produce weed-suppressing cover crops. However, cover crops do not result in weed-free orchards and should be considered within the context of integrated management programs. The apparent flexibility of orchard cover crop management provides an opportunity to promote other agroecosystem services, with vegetation management and weed suppression as complementary management goals.

RNAi knockdown of CAPAr gene affects survival and fecundity of Bemisia tabaci (Gennadius)

Graphical abstract representing the functioning of CAPA receptor in Bemisia tabaci diuresis process and silencing of CAPAr resulting into inactivation of diuresis. • CAPAr gene silencing resulted into significant whitefly mortality. • Reduced fecundity and survival of CAPAr knockdown whiteflies. • Reduced relative gene expression of CAPAr in dsRNA fed whiteflies. Bemisia tabaci (Gennadius) Asia II 1 cause significant economic losses to cotton crop, directly by feeding on sap and indirectly through virus transmission. Although the current control methods are the combination of different tactics but still the chemical control is heavily relied. B. tabaci has gained resistance to majority of the insecticides which has made it difficult to manage this pest using synthetic chemicals. RNAi based gene silencing has been evolved as potential biochemical tool for specific gene silencing of target insect-pest and has been successfully demonstrated for Hemipteran insects. Here, we report the successful silencing of the CAPAr gene in B. tabaci which encodes for the G-protein coupled receptor (a transmembrane membrane peptide). Silencing of CAPAr gene resulted into reduced survival and fecundity of B. tabaci . Oral delivery of dsRNA mediated artificial diet corresponding to CAPAr gene resulted into significantly high adult mortality of 30.74% in treatment dsCAPAr 1.0 µg/µl after 48 hr of dsRNA feeding. A significant reduction in whitefly female fecundity was recorded for all the dsCAPAr concentrations with lowest value of 53.51 eggs per female in dsCAPAr 1.0 µg/µl. The relative gene expression of CAPAr gene further confirms the down regulation of CAPAr gene in knock down adult whiteflies. Our investigation proves the importance of CAPAr for B. tabaci survival and may be exploited as potential tool which can be strategic in integrated management programme for B. tabaci .

Assessment of Selected Commercially Available Seed Treatments on Suppressing the Effects of Red Crown Rot on Soybeans Under a Controlled Environment.

Calonectria ilicicola is a soilborne fungus responsible for red crown rot (RCR) in soybeans. Recently, this disease has been detected in new areas within the United States and Asia, where it has been reported to cause significant yield losses. To date, no data on the efficacy of fungicide seed treatments for suppressing RCR in soybeans are available. We screened three commercially available soybean seed treatments (Acceleron STANDARD; Acceleron STANDARD + IleVO; Cruiser MAXX + Saltro) for impacts on germination, seedling growth, and disease caused by C. ilicicola under controlled laboratory conditions. The Cruiser MAXX + Saltro treatment improved final plant dry mass to levels similar to noninoculated controls. Both Acceleron STANDARD + IleVO and Cruiser MAXX + Saltro reduced percent root rot. Acceleron STANDARD alone did not impact root rot, indicating that the IleVO component was efficacious on C. ilicicola. These data indicate that IleVO and Cruiser MAXX + Saltro have potential for reducing early season impacts of RCR in soybeans. Future work assessing these seed treatments in field-grown soybeans is needed to better understand the role of seed treatments as components of an integrated management program for RCR.