Source: UNIVERSITY OF PUERTO RICO AT MAYAGUEZ submitted to NRP
BIONOMICS OF THE AVOCADO LACE BUG IN PUERTO RICO
Sponsoring Institution
National Institute of Food and Agriculture
Project Status
COMPLETE
Funding Source
Reporting Frequency
Annual
Accession No.
0211460
Grant No.
(N/A)
Cumulative Award Amt.
(N/A)
Proposal No.
(N/A)
Multistate No.
(N/A)
Project Start Date
Aug 15, 2007
Project End Date
Aug 14, 2008
Grant Year
(N/A)
Program Code
[(N/A)]- (N/A)
Recipient Organization
UNIVERSITY OF PUERTO RICO AT MAYAGUEZ
P. O. BOX 9000
MAYAGUEZ,PR 00681
Performing Department
Crops and Agroenvironmental Sciences
Non Technical Summary
The avocado lace bug (ALB) is an economically important and `invasive' pest of avocado in the Caribbean. In Puerto Rico, we estimate losses to be between $200,000 to $1 million dollars per year. Higher estimates are probable in the Dominican Republic and Cuba, where the pest is equally damaging. There is an urgent need to address the losses caused by this `invasive species' in Puerto Rico and in the wider Caribbean, and work in our proposal is designed to drastically reduce its economic impact. We propose to address control needs of this important pest by: (1) increasing our knowledge of this pest's biology and behavior; (2) using population management tactics that use of natural enemy conservation, host phenology, and `reduced risk'; (3) introducing new natural enemies from Florida in an effort at classical bio-control; and (4) researching the effect of host plant characteristics on the avocado lace bug's survival and attack intensity. Field and laboratory experiments are described to determine the effects of three varieties of different parentage, and their leaf-flushing phenology on ALB's life-history parameters. We also propose to determine the identity and importance of natural enemies, and the existence of maternal `guarding' behavior. Further, we propose to search, ship, and introduce key parasitoids from Florida, and evaluate their introduction. Finally, we propose to investigate possible correlations between light intensity at the center of the canopy, and tree architecture to ALB population density and to predation by key natural enemies.
Animal Health Component
75%
Research Effort Categories
Basic
25%
Applied
75%
Developmental
(N/A)
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
2110930113030%
2150930113020%
2160930113050%
Goals / Objectives
(1) Study ALB's life cycle, reproductive behavior, natural enemies, and adaptations to herbivory on avocado .(2) Determine efficiency of registered, and 'reduced risk' pesticides in controlling ALB and their impact on natural enemy populations; (3) Determine importance of components of host plant texture on ALB abundance.
Project Methods
(1) Objective I: This objective seeks to answer several questions about host-plant and trophic interactions. Past research has hinted at ALB's preference for different avocado varieties, and a preference for specific leaf ages and traits. We propose to study the effects of three varieties of different parentage (i.e., subspecific lineage Guatemalan and West Indian), and their leaf-flushing phenology on ALB's life-history parameters. We also propose to determine the identity and likely importance of natural enemies in ALB population dynamics, and the existence of maternal 'guarding' behavior on ALB's survivorship. (2) Objective II: This objective seeks to determine the effects of widely used pesticides on ALB's natural enemies. Current knowledge does not answer this important IPM question for ALB. A comparison on the killing effectiveness of 'reduced risk' pesticides: imidacloprid (0.4kg a.i./a), spinosad (45 ml/acre formulated), and azadirachtin (350 ml/a formulated), plus other more traditional pesticides [permethrin 3.2EC 8 oz/acre, pyrethrins (Pirellin) EC 2 pints/acre], on ALB and its natural enemies will be established in field experiments. Objective III: This objective proposes to investigate possible correlations between light intensity at the center of the canopy, and tree architecture (as determined by apical dominance and acrotony) with ALB population density, and to predation. The hypothesis we test is that ALB populations will be most abundant on trees with lower light intensities at their center, as determined by weak apical dominance and weak acrotony.

Progress 08/15/07 to 08/14/08

Outputs
OUTPUTS: Natural enemies of the avocado lace bug (ALB) were identified, with very few species in very low numbers associated with predation. No egg or nymphal parasitism was found. We did identify two generalist predators attacking nymphs: Coleophora inaequalis (Coleoptera: Coccinellidae), Chyrisopa sp. and an unidentified hemerobiid neuropteran (Neuroptera: Chrysopidae). Larvae of these were frequently observed feeding on colonies. Among pesticides tested to control the pest, imidacloprid and permethrin 3.2EC were the most effective. Of the organically approved products azadirachtin was the most effective, followed by pyrethrins (Pyrellin) and spinosad. Sampling trials showed that most ALB colonies and individuals tend to be aggregated around the second branch internode in young avocado trees. This finding is significant because it confirms previous observation on ALB's preference for mature (but not senescing leaves) as feeding/oviposition sites. Further female oviposition patterns indicate a preference for fully expanded new leaves during oviposition. We hypothesize that this would be the critical moment for application of sprays. Our data also show that colonies prefer being on the south eastern quadrant of the tree. Further observations confirm that after 20 weeks of sampling, varieties Avila and Wilson Popenoe showed significantly more ALB attack than other cultivars. Cultivars Simmonds and Semil 34 showed the least attack. Weekly census data also confirm the presence of low populations during the month of August, when trees are in their summer dormant period. Two attack peaks were observed in March and in November, following leaf flushes. PARTICIPANTS: One graduate assistantship was granted from this funding and an M.S. thesis was prepared. Three graduate seminars were prepared. Participants were Alberto Velez, Luisa Lopez, Edward Roa (graduate student), Lucero Alcazar, Irma Cabrera, and Alejandro Segarra. TARGET AUDIENCES: Target audiences were students and extension professionals PROJECT MODIFICATIONS: Not relevant to this project.

Impacts
Our finding of few natural enemies attacking the ALB indicates that the classical biological control is still a good option to manage this important pest. Efforts should still be made to search for and introduce natural enemies from Florida. Originally this was an objective of this research, which was cancelled because of lack of funding. The ALB is still an important pest on for the avocado industry and further attempts to introduce natural enemies should be considered a priority. Our data demonstrate that azadirachtin can be used successfully to lower ALB, thus providing a safer control alternative. This result coupled with our finding of critical oviposition times following avocado leaf flushes can be used effectively in an IPM program against this pest.

Publications

  • No publications reported this period