Performing Department
ENTOMOLOGY
Non Technical Summary
Apple and blueberry are two important fruit crops in the United States, adding $3.05 billion and $614.4 million to country economy respectively. Spotted wing drosophila (SWD) and apple maggot fly (AMF) are one of the most important pests of blueberry and apple respectively. Current management practices for both pests rely on frequent applications of broad-spectrum, particularly organophosphate and pyrethroids, the reduced risk spinosyns, and on cultural control. Biological based control using entomopathogenic nematodes (EPNs) and fungi (EPF) is a promising alternative to chemical insecticides. In our previous laboratory study, we found EPNs very effective against AMF. Different species of EPF have been tested against the variety of insect pest species including AMF under laboratory condition. Previously, only a limited numbers of EPN and EPF species were evaluated against SWD. In this project, we plan to screen a diverse array of EPNs and EPF under laboratory and greenhouse against soil dwelling stages of SWD and AMF. This project also seeks to evaluate environmental constraints on pathogen's efficacies and compare different novel formulations of EPNs for SWD and AMF management. After evaluating EPNs and EPF singly, we then propose to test the efficacy of combined applications of both agents. Along with laboratory and greenhouse trials, we will conduct the trials at growers field to assess the pathogenicity of EPNs and EPF under field conditions. The result and outcomes of this series of studies are expected to help growers reduce losses caused by SWD and AMF.
Animal Health Component
80%
Research Effort Categories
Basic
20%
Applied
80%
Developmental
0%
Goals / Objectives
For this project, we designed three different research objectives (80% of total effort) and one Extension (20% of total effort) distributed over a 3-year period. If we get promising results from field applications, then we will recommend growers to include EPNs and EPF applications into their existing IPM plans against SWD and AMF.Research Objective 1: To quantify the pathogenic potential of EPNs against the soil-dwelling stages of SWD and AMF in laboratory, greenhouse, and field cage trials.We hypothesize that EPNs will reduce adult emergence of SWD and AMF when compared with control group. Reduction in adult emergence is expected to be dose dependent and EPNs with novel formulations will provide better control compared with application of EPN singly or control group (untreated). Direct application of EPNs singly or in combination with novel formulations on blueberries will reduce the number of hibernating larvae/pupae inside fruits.Anticipated impact: We expect to identify at least one potential EPN species in combination with a novel formulation for potential use by growers.Research Objective 2: To quantify the virulence of EPF against soil dwelling stages of SWD and AMF in laboratory, greenhouse, and field cage trials.We hypothesize that EPF will significantly reduce adult emergence of SWD and AMF when compared with the control group. Reductions in adult emergence will be dose dependent and temperature dependent.Anticipated impact: We will recommend growers at least one or two EPF singly to manage SWD and AMF in under field conditions.Research Objective 3: To assess the types of interaction (synergistic, additive, antagonistic) existing between EPNs and EPF under laboratory, greenhouse, and field cage conditions.We will test the hypothesis that a combination of EPNs and EPF will provide greater levels of suppression of SWD and AMF compared with single application of each agent and the control group.Anticipated impact: This information is expected to inform growers on whether to use combined versus single biocontrol agents.Extension objective: To disseminate research results with the grower and academic community via targeted Extension programming in Michigan and Massachusetts and neighboring states.Anticipated impact: Through our on-farm demonstrations and communications with growers, growers will become aware of the potential application of EPNs and EPF into existing IPM programs against SWD and AMF.
Project Methods
Research objective 1: To quantify the pathogenic potential of EPNs against the soil-dwelling stages of SWD and AMF in laboratory, greenhouse, and field cage trials.1.1. EPN screening bioassay: Ten EPN strains will be screened in this project using methodologies mostly developed by our team. Five of them (S. carpocapsae, S. riobrave, S. feltiae, H. bacteriophora, and H. megidis) are commercially available against several insect pest species (Usman et al. 2021a).1.2. Virulence bioassay: Here, we will evaluate various application rates of EPNs. In a more focused virulence bioassay, we will use the same methodology except only the five best EPNs will be applied at four different concentrations (25, 50, 75, and 100 IJs cm-2) (Usman et al. 2021a).1.3. Environmental tolerance bioassays: We will assess novel formulations (barricade, liquid starch, and white kaolin clay) of EPNs which are expected to enhance EPNs tolerance to temperature (20oC, 25oC, 30oC) and increase their virulence to SWD and AMF. We will use the two best performing EPN species for SWD and best rate based on the result of the previous bioassay (virulence bioassay) (Mastore et al. 2023; Wu et al. 2023). For AMF, we will use S. riobrave and S. carpocapsae at the best rate (Usman et al. 2020a).1.4 Greenhouse bioassay: The objective of this experiment is to assess the application of EPNs and best formulation against SWD and AMF under greenhouse conditions. We will use the two best performing EPN species and best rate for SWD based on the result of the previous bioassay (virulence bioassay). For AMF, we will use S. riobrave and S. carpocapsae at the best rate (Usman et al. 2020a). We will follow the methodology of Usman et al. (2021a).1.5 Field cage bioassays: We will perform two different types of field cage experiments, one field cage trial with infested fruits and other field cage trial with pupae inside the soil (Heve et al. 2018; Usman et al. 2021a).Research Objective 2: To quantify the virulence of EPF against soil dwelling stages of SWD and AMF in laboratory, greenhouse, and field cage trials.2.1 EPF virulence screening bioassay against pupae: We will identify the best EPF and their best rate. Four different commercial strains of EPF will be tested at three different rates ranging from 1.0 × 106 to 1.0 × 108 conidia ml-1 (Usman et al. 2021b).2.2 Environmental tolerance bioassay: The objective of this is to determine the possible effect of different temperatures on efficacy of EPF against SWD and AMF. From virulence screening bioassay, we will select only two EPF with the best rate for this experiment. We will use similar protocol of previous experiment except we will expose different treatments to different temperatures (20oC, 25oC, 30oC) in an incubator (Mastore et al. 2023).2.3 Greenhouse bioassay: The objective of this experiment is to assess the application of EPF and best rate against SWD and AMF under greenhouse conditions. We will use the two best performing EPF species and best rate for SWD and AMF based on the result of the previous bioassay (virulence bioassay) (Usman et al. 2021b).2.4 Field cage bioassay: We will perform efficacy of potential EPF against soil dwelling stages of SWD and AMF in field cage bioassay at Michigan and Massachusetts (Usman et al. 2021b).Research Objective 3: To assess the types of interaction (synergistic, additive, antagonistic) existing between EPNs and EPF under laboratory, greenhouse, and field cage conditions.3.1 Small cup bioassay: We will use the rate of EPF and EPNs that will give 50% of mortality based on our previous experiments. We will use best two EPNs and EPF from our previous experiment and will use different treatments: (T1) EPF1 applied singly, (T2) EPF2 applied singly, (T3) EPN1 applied singly, (T4) EPN2 applied singly, (T5) combined application of EPF1 and EPN1, (T6) combined application of EPF1 and EPN2, (T7) combined application of EPF2 + EPN1, and (T8) combined application of EPF2 + EPN2. We will follow the methodology of (Usman et al. 2022; Wakil et al. 2022).3.2 Pot soil bioassay: The objective of this bioassay is to determine the interaction between EPNs and EPF against SWD and AMF in a large pot bioassay with more soil in a laboratory condition. The methodology will be as described by Usman et al. (2020b) except that we will use pots with more soil (Usman et al. 2020b, Wakil et al. 2022).3.3 Greenhouse bioassay: The objective of this bioassay is to determine the efficacy of single versus combined application of EPNs and EPF in the greenhouse (Usman et al. 2020b, Wakil et al. 2022).3.4 Field cage bioassay: A field cage trial will be conducted at blueberry farm and at an apple orchard inMichigan and Massachusetts, respectively (Wakil et al. 2022).