Below is a quick overview of current and past research, broken apart by the crop and associated pests.
Rice
In rice, we have been working to design IPM programs for key pests that employ reduced-risk tools (including biocontrol) and that best use insecticides through scouting and damage thresholds. In a common theme for many crops we work with, pyrethroids are the current primary driver of insecticide use in rice. We have been investigating alternative materials and application timings for tadpole shrimp to better permit monitoring. High use of pyrethroids has led to scattered pyrethroid resistance in tadpole shrimp, so we are currently surveying and documenting resistance levels across the rice-growing region and addressing other aspects of resistance. We have also employed CAD and 3D printing to create a sampling device to facilitate an IPM-focused approach to shrimp management.
Another pest, armyworm, can show up in high numbers quickly and rapidly defoliate rice. Few materials are registered, so tested novel materials. We also clarified damage thresholds, both mid-season and when rice is heading. Why outbreaks occur and where they occur has been a mystery, so we have had a number of projects on pheromone trapping to better predict damage. This includes work on automated traps, spatial and temporal variability in trap captures, and linkages between moth flights and larval populations.
Cotton
In cotton, lygus, whiteflies, and aphids are the most problematic pests and we are currently continuously evaluating tools for their management. Aphids and whiteflies can be particularly challenging mid- to late-season pests that threaten cotton production because they produce sticky honeydew, which contaminates cotton lint and creates “sticky cotton.” We are evaluating new materials that may help prevent sticky cotton. In addition, we are examining the interplay between coverage and efficacy of insecticides because good coverage can be difficult to achieve once cotton has grown tall and the canopy has filled out. Lygus has been a problematic pest for many years, and we are continuing to conduct research aimed at improving management plans for this pest. This has focused on optimizing einsecticide use with an emphasis on materials that are both effective and selective. Selectivity can be key to maintain natural enemies that could target lygus, but also other pests like aphids, whiteflies, and mites.
Alfalfa
Our work in alfalfa has focused on several key pests. Primarily, we are working on alfalfa weevil and addressing management issues that stem from insecticide resistance. Pyrethroid insecticides are currently the go-to management tool in conventional systems, but reports have been simmering across the Western US and the the US more broadly (and into Canada) of resistance. Given the lack of many modes of action for alfalfa weevil, this is a significant concern. We are working as part of a broader project (Resistant Alfalfa Weevil Project [RAW], link) to identify the scope or resistance and to better address resistance management. In addition, we are working to evaluate newer, more selective materials for aphids, especially blue alfalfa aphid. This pest can be challenging to manage, especially in higher elevation areas where it can attack alfalfa just coming out of dormancy. Selective materials that preserve natural enemies are valuable tools for this pest and we are working to understand how they fit within the system.
Lettuce
We are currently working on developing better IPM plans for aphids and thrips. This has included novel uses of insecticides and biological control. Both pests can be problems in organic and conventional systems. We are examining different application methods of insecticides, including different at-planting methods as well as precision applications using automated thinners. For biological control, we are evaluating how effective drone released natural enemies are for these pests and aim to develop best practices for releases. We are also determining how non-crop habitat, both within-field and across the broader landscape could help support natural enemies and the services they provide.
Cole crops
Diamondback moth is the most problematic pest in CA cole crops currently. Damage and control costs are extremely high in many areas. We are working on different aspects of diamondback moth management, including mating disruption, non-crop host use, dispersal, biological control by parasitoids, and insecticide resistance. /span>
Melons
Cucumber beetles, especially the western striped cucumber beetle, are problematic in melons in both organic and conventional systems. We are taking a multi-pronged approach to improve IPM, evaluating insecticides as well as novel tools that incorporate pest ecology. Our projects have been investigating the non-crop habitat use and seasonal dynamics of cucumber beetles in farm landscapes with the goal of improving monitoring and potentially managing beetles outside of crop fields. We have also been examining novel attractants that might be useful for monitoring and management.