Skip to main content
ARS Home » Pacific West Area » Corvallis, Oregon » Horticultural Crops Research Unit » Research » Publications at this Location » Publication #317985

Title: Characterization and manipulation of fruit susceptibility to Drosophila suzukii

Author
item Lee, Jana
item DALTON, DANIEL - Oregon State University
item SWOBODA-BHATTARAI, KATHARINE - Oregon State University
item BRUCK, DENNY - Dupont Pioneer Hi-Bred
item BURRACK, HANNAH - North Carolina State University
item STRIK, BERNADINE - Oregon State University
item WOLTZ, JESSICA - Oregon State University
item WALTON, VAUGHN - Oregon State University

Submitted to: Journal of Pest Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/17/2015
Publication Date: 8/27/2015
Citation: Lee, J.C., Dalton, D.T., Swoboda-Bhattarai, K., Bruck, D.J., Burrack, H.J., Strik, B.C., Woltz, J.M., Walton, V.M. 2015. Characterization and manipulation of fruit susceptibility to Drosophila suzukii. Journal of Pest Science. 89(3):771-780. doi: 10.1007/s10340-015-0692-9.

Interpretive Summary: Spotted wing drosophila (SWD) is an economic pest of small fruits and cherries that lays its eggs into intact ripening fruits. Host susceptibility is influenced by characteristics of the fruit such as flesh firmness, penetration force of the skin, sweetness (TSS or °Brix) and acidity (pH). To develop thresholds and risk prediction models for IPM, it is helpful to know at what firmness or pH level that a fruit becomes more susceptible to attack. First, a direct bioassay was used to calculate the probability of egg laying in a given fruit based on various characteristics across five trials in the laboratory or field. Probability of egg laying and number of eggs deposited into fruit consistently decreased as penetration force increased. Egg laying sometimes decreased as flesh firmness increased, and sometimes increased as TSS and pH increased. Second, raspberries and blueberries in unsprayed fields were observed to have substantially lower infestation in ripening fruit than in ripe fruit, and no or minimal infestation of green fruit. Given that skin firmness influences egg laying, cultural practices used to improve fruit quality were examined for potential reduction of egg laying. Blueberry fruit sprayed with calcium silicate in the field showed reduced numbers of eggs laid by SWD in laboratory no-choice cages compared to gibberellic acid-treated fruit. None of the other treatment compounds of chelated calcium, calcium borate, and an anti-cracking biofilm differed from the control or from each other. Calcium-based treatments increased Ca content, firmness, and penetration force of fruit relative to untreated fruit.

Technical Abstract: Drosophila suzukii (Matsumura) is an economic pest of small fruits and cherries that attacks intact ripening fruits. Host susceptibility is influenced by characteristics such as flesh firmness, penetration force of the skin, total soluble solids (TSS, also known as °Brix) and pH. Improved knowledge of fruit susceptibility is needed for developing thresholds and risk prediction models for IPM. First, a direct bioassay was used to calculate the probability of oviposition in a given fruit based on various characteristics as determined across five trials in the laboratory or field. Probability of oviposition and number of eggs deposited into fruit consistently decreased as penetration force increased. Oviposition sometimes decreased as flesh firmness increased, and sometimes increased as TSS and pH increased. Second, raspberries and blueberries in unsprayed fields were observed to have substantially lower infestation in ripening fruit than in ripe fruit, and no or minimal infestation of green fruit. Given that skin firmness influences oviposition, cultural practices used to improve fruit quality were examined for potential reduction of oviposition. Blueberry fruit sprayed with calcium silicate in the field showed reduced numbers of eggs laid by D. suzukii in laboratory no-choice cages compared to gibberellic acid-treated fruit. None of the other treatment compounds of chelated calcium, calcium borate, and an anti-cracking biofilm differed from the control or from each other. Calcium-based treatments increased Ca content, firmness, and penetration force of fruit relative to untreated fruit.