Strawberry pre plant meetings 2020 Pest management considerations

Strawberry pre plant meetings, 2020 Pest management considerations Pollination biology Hannah Burrack, Professor & Extension Specialist Jeremy Slone, Ph. D Graduate Laura Kraft, Ph. D Student Department of Entomology & Plant Pathology

Topics • Pest management considerations • Spider mite management • SWD significance and control

Spider mite control basics • Start scouting in early spring, when daytime temperatures start exceeding 50 F • Treat is populations greater than 5 mites/leaflet are present pre fruiting • Avoid pyrethroid insecticides when mites are present • If using predatory mites, do not use oils or soaps for spider mite control post predator release

Conventional spider mite control options Material Agri-Mek Savey Zeal Acramite Vendex Kanemite Oberon Portal Nealta IRAC Group 6 10 A 10 B 20 D 12 B 20 B 23 21 A 25 Target life stage Motiles Immatures Motiles, some egg Immatures, some adult Motiles All stages Efficacy Rating (1 -4) 3 3 3 4 2 4 4 3 4

Screening spider mites for resistance

Screening spider mites for resistance – NC Populations CF - Strawberries ** Laboratory population UT C ta al Ne l rta ite Po m ne Ka Ac ra m ite x de Ve n Ag r Br i-M ek * iga de UT C ta Ne al l rta m ne Po x de Ve n Ag r i-M ek iga de ite Ac ra m ite * * Br 1 0. 8 0. 6 0. 4 0. 2 0 Ka 1 0. 8 0. 6 0. 4 0. 2 0 WA - Watermelon WM - Strawberries 1 0. 4 *No different than control **Better than control, but weaker than other materials Greater variability among adulticides. Brigade and Vendex ineffective. C UT ta al Ne l ta Po r ite m Ac ra ite ex nd Ve ek M de iga Br C UT ta al Ne l ta Po r m am ite Ac r ite 0 ex Ve nd ek M Ag ri- de iga Br * 0. 2 m * 0 ne 0. 2 ** ** 0. 6 Ag ri- ** 0. 4 0. 8 ** Ka 0. 6 ne 0. 8 Ka 1

Screening spider mites for resistance – SC Populations Paul Bergeron & Rebecca Schmid-Jeffris (USDA ARS)

Screening spider mites for resistance – SC Populations Adulticides Paul Bergeron & Rebecca Schmid-Jeffris (USDA ARS)

Screening spider mites for resistance – SC Populations Ovicides Paul Bergeron & Rebecca Schmid-Jeffris (USDA ARS)

Screening spider mites for resistance – SC Populations Paul Bergeron & Rebecca Schmid-Jeffris (USDA ARS)

Acknowledgements Paul Bergeron & Rebecca Schmid-Jeffris (USDA ARS) Jim Walgenbach

Spider mite control basics • Start scouting in early spring, when daytime temperatures start exceeding 50 F • Treat is populations greater than 5 mites/leaflet are present pre fruiting • Avoid pyrethroid insecticides when mites are present • If using predatory mites, do not use oils or soaps for spider mite control post predator release

SWD in strawberries • Fall fruiting berries are at high risk • In most years, the small infestation present can be managed through cultural control Western North Carolina, 2011 Total SWD per week • Spotted wing drosophila (SWD) is not a consistent pest in spring-fruiting strawberries

SWD in strawberries – May be a post harvest concern

Two types of studies Field-Infested Fruit Laboratory-Infested Fruit

Mean D. suzukii 20 18 16 14 12 10 8 6 4 2 0 Field-infested Strawberry df=6, 18; F=9. 70; p<0. 0001 b a 0° C for 2. 2° C for 120 hr 96 hr 72 hr 20° C

Laboratory-Infested Strawberry Mean D. suzukii 100 90 80 70 60 50 40 30 20 10 0 0° C for 120 h 0° C for 96 h 0° C for 72 h 100 90 80 70 60 50 40 30 20 10 0 Egg 0° C for 120 h 0° C for 96 h 0° C for 72 h 20° C 100 90 80 70 60 50 40 30 20 10 0 2 nd Instar 20° C 1 st Instar 20° C 3 rd Instar 0° C for 120 h 0° C for 96 h 0° C for 72 h 20° C

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