Developing farmer- appropriate integrated pest management strategies in South Texas: The potential of push-pull technologies to regulate organic brassica pest

View the project final report

Commodities

• Vegetables: greens (leafy)

Practices

• Pest Management: integrated pest management

Habitat management strategies that increase the functional agrobiodiversity of agroecosystems have been associated with reductions in the number of many herbivore pests, in temperate, subtropical and tropical cropping systems. Increasing the functional diversity of agroecosystems by combing crops with non-crop, secondary plant functional groups that provide resources for natural enemies and/or alter the behavior and distribution of pests has been a particularly effective approach to pest management. A common form of functional diversification strategy used in IPM is the push-pull approach, or the spatial integration of secondary plant species with pest attractant and repellent stimuli within agroecosystems. Typically, repellent plants (the "push" component) are placed within close physical proximity of a field (the "pull" component). The net movement of pest species is therefore away from the susceptible crop area and into a nearby stand of attractant plants. While push-pull approaches are pest-specific, they can also be developed to lure beneficial insects towards the source of concentrated pest populations to maintain pest numbers lows and reduce pest spillover into the crop. The incorporation of natural enemy and pest attractant plants within fields and along field margins has been shown to substantially increase parasitism and mortality levels in multiple species of aphids.

We propose utilizing a push-pull technology to manage pests in South Texas. While push-pull pest management is by no means a new approach, it will be innovative for the South Texas region, as little is known on the role of deploying repellent and attractant plants in tandem in order to reduce pest populations in agricultural fields. Furthermore, organic farmers in the South Texas region have expressed interest in using push-pull technologies to control pests, and played a pivotal role in the development of push-pull pilot studies in the spring 2014 growing season. The results not only informed the experimental design of this proposed research, but also indicated farmer willingness to test and potentially adopt push-pull technologies for pest management.

We will establish a randomized block experimental design to test the effectiveness of push-pull technologies in managing pests of organic kale fields. We will incorporate plants that emit pest repellent, attractant, and natural enemy attractant properties in plots and measure the abundance and distribution of pest and natural enemy distribution and abundance in kale. The "pull" component will comprise a cocktail of fennel, dill and alyssum planted along field margins, while the "push" component will be intercropped within kale fields and will consist of two treatments: cilantro and onions.

We will track the abundance of three major brassica pests on kale plants over 4 months: the green peach aphid, cabbage looper, and beet armyworm. We will also test for relationships in pest densities and natural enemy diversity found on kale plants and surrounding pull plants.

We predict that pest abundances and natural enemy diversity levels will be lower on kale plants in push-pull treatments relative to control; pest densities on sampled kale plants will be negatively associated with pest abundance in surrounding pull plant strips; and natural enemy diversity on sampled kale plants will be positively associated with natural enemy diversity in surrounding pull plant strips.