Project Overview
Commodities
- Fruits: avocados
Practices
- Pest Management: economic threshold
Proposal abstract:
Avocado lace bug (ALB), Pseudacysta perseae, is a phloem-feeding insect pest of avocado trees and is invasive to California, Florida, and Hawai’i. Feeding by ALB nymphs leads to the accumulation of large areas of necrosis on avocado leaves and eventual tree defoliation. ALB-induced leaf necrosis begins as areas of chlorotic tissue that grow larger as nymphs eclose, feed, and develop. Eventually, these necrotic areas become sufficiently large that the leaves are dropped from the tree prematurely. A sufficient number of early leaf drop events between periods of flowering and fruit set in avocado trees has been suggested to negatively affect avocado yield, likely through decreased photosynthetic activity and reallocation of resources to new leaf growth. However, at this time it is unclear how much tree defoliation (premature leaf drop) must occur for yield effects to justify the costs of management. For avocado growers in Hawai’i, this ambiguity has led to the inefficient use of various pesticide management programs and has resulted in further economic losses, pesticide exposure to surrounding residential and natural areas, and fragility in food security for the state. Our project will investigate the association between tree defoliation and avocado yield loss from accumulated ALB damage. From these results, we will develop economic threshold models that avocado growers will be able to use as management tools for controlling ALB populations. These economic thresholds will be based on initiating management programs when certain thresholds of leaf damage across a tree are exceeded during a fruiting season. We will conduct pesticide trials using these damage thresholds and soil drenches of Admire®Pro (Bayer Crop Science) to determine yield effects associated with varying degrees of ALB damage. From these findings we will be able to derive economic injury levels and develop threshold models for the Admire®Pro soil drench program and several organic foliar spray programs. From this project, we will improve stakeholder and grower knowledge of how avocado lace bug (ALB) damage affects fruit yield, what economic threshold models are and how they can be used in management programs for ALB, and how basing management on economic thresholds can help create a more sustainable agricultural environment for Hawai’i. We will do this by (a) conducting field demonstrations on monitoring ALB damage on-farm, (b) summarizing ALB damage monitoring and economic thresholds through accessible extension documents and scholarly articles, (c) creating accessible online video demonstrating ALB life history, damage monitoring, and economic threshold management, and (d) disseminating project results at Hawai’i grower meetings. We anticipate that results from this project will decrease economic loss for avocado growers while also reducing pesticide exposure to growers and surrounding residential/natural areas as well as help maintain crop type diversity to aid in offsetting food insecurity in Hawai’i. The management tools developed from this project will be applicable to avocado growers in other affected areas of the USA such as California, Florida, Texas, and Puerto Rico.
Project objectives from proposal:
Research Objectives:
- Determining an optimized subsampling method
- Conducting pesticide trials
- Examining proportion threshold effects on avocado fruit yield
- Developing an economic threshold model
- Developing economic threshold models for organic management programs
Educational Objectives:
- Conducting field demonstrations on monitoring ALB damage
- Summarizing ALB damage monitoring and economic thresholds through accessible extension documents and scholarly articles
- Creating accessible online video demonstrating ALB life history, damage monitoring, and economic threshold management
- Disseminating project results at Hawai’i grower meetings