Dissertation
THE EFFICIENCY OF THE GRAPE MEALYBUG, Pseudococcus maritimus, TO VECTOR GRAPEVINE LEAFROLL ASSOCIATED VIRUS-3
Doctor of Philosophy (PhD), Washington State University
01/2020
Handle:
https://hdl.handle.net/2376/108555
Abstract
Grapevine leafroll disease (GLD) is the most economically important viral disease in wine grapes (Vitis vinifera L.). In Washington State vineyards, the grape mealybug, Pseudococcus maritimus (Ehrhorn; Hemiptera: Pseudococcidae), is the primary vector of Grapevine Leafroll associated Viruses (GLRaVs) which are the causal agents of GLD. While grape mealybug is a known vector, it was unknown how efficient this vector was at spreading GLD.
Rearing laboratory colonies of grape mealybug has proven difficult. Several host plants were tested to determine their suitability for use as an alternate host plants for laboratory colonies of grape mealybug. Of the plants tested, colonies of grape mealybug were successful on pumpkin (Cucurbita pepo cv ‘Connecticut field’) leaves and vines. Mealybugs were able to develop from the crawler stage, through developmental instars, and adults were able to reproduce viable offspring.
In greenhouse transmission bioassays we tested infestations of five and one GLRaV-3 infected grape mealybug crawlers per grapevine (cv. ‘Chardonnay’) to see if transmission occurred. The five grape mealybug per vine treatment had transmission occurred in six out of the twenty recipient vines by year two. The one grape mealybug per vine treatment had transmission occurred in two out of the twenty recipient vines in both the first and second year tested. Our experiment confirmed an earlier predicted estimate that feeding by a single GLRaV-3 infected grape mealybug had the probability of transmission of 0.10 ± 0.003.
Current control recommendations for slowing the spread of GLRaVs include one to two applications of insecticides to reduce vector populations. Systemic insecticides require the insect to feed before death or paralysis occurs. It was unknown if systemic insecticides could paralyze or kill grape mealybug quickly enough to reduce their ability to vector GLRaVs. Hence, we tested imidacloprid, spirotetramat, and flupyradifurone to see if these insecticides would have any effect on grape mealybug’s efficiency to vector GLRaV-3 on treated grapevines. We conclude that these systemic insecticides do not convey any additional protection to grapevines. However, these insecticides are still useful for reducing vector populations and indirectly reduce the potential spread of GLRaVs among vines in vineyards.
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Details
- Title
- THE EFFICIENCY OF THE GRAPE MEALYBUG, Pseudococcus maritimus, TO VECTOR GRAPEVINE LEAFROLL ASSOCIATED VIRUS-3
- Creators
- Jonathan Scott O'Hearn
- Contributors
- Douglas B. Walsh (Advisor)Naidu A. Rayapati (Committee Member)Richard S. Zack (Committee Member)Alan S. Felsot (Committee Member)
- Awarding Institution
- Washington State University
- Academic Unit
- Entomology, Department of
- Theses and Dissertations
- Doctor of Philosophy (PhD), Washington State University
- Number of pages
- 84
- Identifiers
- 99900581812401842
- Language
- English
- Resource Type
- Dissertation