Factors Limiting Peach as a Potential Host for <I>Drosophila suzukii</I> (Diptera: Drosophilidae)

Abstract

The spotted wing drosophila, Drosophila suzukii Matsumura, has widely established in North America and become an economic concern for a variety of fruit crops. To better understand fruit susceptibility, we evaluated peach surface characteristics on the pest's oviposition success. The number of D. suzukii eggs laid into the fruit flesh was tested on 1) peaches with or without indumenta (commonly referred to as peach fuzz), 2) peaches physically damaged by harvest operations, 3) peaches damaged by the peach twig borer Anarsia lineatella Zeller or the forktailed bush katydid, Scudderia furcata Brunner von Wattenwyl, and 4) peaches with punctures that simulated stink bug damage. Female D. suzukii did not lay eggs in intact fuzzy sections of the fruit or into small punctures (0.3 or 0.5 mm), but readily laid eggs in sections without fuzz, with insect damage, and with large punctures (1 mm). The number of eggs per treatment was positively related to the area of the damaged section; the overall fruit firmness and sugar content was not related to the number of eggs laid in treated or damaged spots. Direct observations of D. suzukii oviposition confirmed that peach fuzz appeared to be an obstacle for the fly's oviposition success, and female flies ceased ovipositional attempts on fuzzy peach sections after a short period of time. Successful oviposition times were associated with substrate firmness, with shorter oviposition time in damaged spots than in cherry fruit or shaved spots of the peach. The results indicate that intact, preharvest peach fruit are unlikely to be infested by the fly, but any surface damage could render the fruit susceptible to the fly.

Development, Reproductive Output and Population Growth of the Fruit Fly Pest <I>Drosophila suzukii</I> (Diptera: Drosophilidae) on Artificial Diet

“…For instance, picking scars and other forms of harvest damage to non-host fruits such as peaches can induce D. suzukii females to lay 4 times more eggs than insect damage does and 10 times more eggs than simulated damage does (Stewart et al 2014). Hence, fruit marred from hail and during harvest might possibly increase market losses to D. suzukii infestation.…”

“…Sampson, personal observation). These misplaced eggs withered without larval hatch (Stewart et al 2014). Drosophila suzukii females can easily lay eggs in blueberry and blackberry fruits, two hosts with thin skins.…”

“…This behavior suggests blueberry is a less preferred reproductive host, and does explain lower mean yield losses for blueberry when compared with other cultivated small fruits, notably brambles (Burrack 2014). Successful oviposition occurs only after the female vertically inserts eggs into the mesocarp with their paired respiratory (oxygen) filaments projecting above the puncture site (Stewart et al 2014). Hence, the ratio of viable eggs (successful oviposits) to aborted or misplaced eggs might serve as an excellent index for measuring host plant resistance.…”

“…Two dozen of D. suzukii's crop hosts yield berries with an exocarp thin enough for ovipositors to puncture. Some of these crops include globally important and high-value fruit species including stone fruits (peaches, cherries, and apricots), blueberries, overripe grapes, citrus, apples, pears, persimmons, figs, and pomegranates (Price et al 2009;Beers et al 2011;Stewart et al 2014).…”

“…Although D. suzukii related articles based on laboratory tests briefly describe diet methodology, none mentions incidences of disease, use of antibiotics, or the contributions of the diet's ingredients to fly nutrition and rearing success. Fruit-amended diets for D. suzukii commonly have included purees of fresh fruit, either peach or raspberry, with (Stewart et al 2014) or without the addition of an agar thickener (Hardin et al 2015). Whole berries (e.g., raspberries), one or perhaps more, can be dropped into a rearing vial onto the soft diet media (Kacsoh & Schlenke 2012).…”