Stink Bug Management on Tomatoes
Transcription
Stink Bug Management on Tomatoes
Stink Bug Management on Tomatoes Celeste Welty Extension Entomologist Ohio State University January 2003 Stink Bug as a Tomato Pest » Bugs suck on fruit » Damage seen more often than bug itself » Damage often not noticed until harvest » Problem on whole-pack & fresh market varieties Stink Bug Damage on Tomato » Obvious yellow blotch: • Develops after fruit ripens if bugs fed on green fruit » Subtle white cloudy-spot: • Seen after bugs fed on red fruit Stink Bug Damage on Tomato yellow blotch cloudy spot » Diagnose by plugs of white tissue under the peel Most common species in tomato fields: the one-spotted stink bug (Euschistus variolarius) Stink bug life stages » Eggs » Nymphs (5 instars) » Adult Lab study to characterize stink bug damage, 1996 » Start with hatching egg, end with new adult » One bug per dish with: • 1 green fruit • 1 red fruit • 1 leaf » Fresh set-up every 4 days Mean % of time Stink bug behavior on tomato: Location in observation arena 100 90 80 70 60 50 40 30 20 10 0 Red fruit Green fruit Leaf Dish 1 2 3 4 Instar 5 6 (adult) % of fruit surface damaged Percentage of tomato fruit surface damaged by stink bugs during 4-day periods from egg hatch to adult eclosion 50 40 30 Green fruit Red fruit 20 10 0 1 2 3 4 5 6 7 8 9 Time period Corresponding instar: I-II II-III II-III III-IV III-V IV-V V-Ad V-Ad V-Ad Damage depth rating Depth of feeding damage by stink bugs on tomato during 4-day periods from egg hatch to adult eclosion Green fruit 3 Red fruit 2 1 0 1 2 3 4 5 6 7 8 9 Time period Corresponding instar: I-II II-III II-III III-IV III-V IV-V V-Ad V-Ad V-Ad Short lab study to further characterize bug damage, 1997 » Compare stink bug & tarnished plant bug » Start with nymph or adult » One bug per dish with: • 1 green fruit • 1 red fruit » Fresh set-up every week for 2 weeks 50 green fruit 40 red fruit 30 20 stink bug nymph to adult TPB,wk2 TPB,wk1 SBNA,wk2 stink bug adult SBN,wk1 0 SBA, wk2 10 SBA,wk1 % of surface affected Damage by bugs feeding on red vs green tomato fruit in two week test tarnished plant bug Stink Bug Feeding Behavior Conclusions » Fruit preference: • Bugs prefer green fruit over red fruit » Life stages: • Adults & all nymph stages feed on fruit • Older nymphs and new adults feed more than younger nymphs and older adults » Tarnished plant bug rarely feeds on tomato fruit even if starved Stink Bug on Tomato » when does it enter tomato fields? » where does it come from? Stink Bug Scouting, 1998 Site First damage Central Ohio: » Columbus » Miami Co. » Darke-D » Darke-K » Darke -H 7/2 7/16 7/15 7/15 8/12 (latest) Northern Ohio: » Sandusky-H » Sandusky-B » Sandusky-V 6/22 (earliest) 7/8 7/6 One-Spotted Stink Bug: the wheat connection 1998 observations in wheat, Fremont: » 15 - 29 May: » 14 - 24 June: » 29 Jun.-1 Jul.: » 1-2 July: Stink bug adults (old) Stink bug nymphs Nymphs & adults (new) Adults in combined wheat Stink Bug Dispersal from Wheat to Tomato Fremont, 1998: % of samples damaged (10 samples/ bed) Wheat Tomatoes Soybean Bed Bed Bed Bed Bed #1 #5 #10 #20 #37 6/22 0 0 0 0 0 7/1 0 0 0 0 0 7/2-3 harvest 7/6 20% 10% 10% 0 10% 7/15 0 0 0 0 0 7/20 20% 50% 20% 0 10% 7/29 80% 70% 40% 50% 70% 8/3 30% 50% 40% 30% 90% 8/14 10% 50% 60% 30% 50% Life History of the One-Spotted Stink Bug, Euschistus variolarius » overwinter in alfalfa? » one generation in wheat, May-June » move to tomatoes (or soybeans) in July, August Stink Bug Control » Action threshold? » Which insecticide? Fremont Ohio, 1999 30 20 Spray 8/3 ● adult ❍ nymph ■ fruit damage ■ Spray 8/23 10 plants @ 32 plots 100 fruit @ 32 plots ❍ ● ❍ ● 8/31/99 ● ❍ ● 8/17/99 ■ 8/11/99 ❍ ● 7/27/99 ❍ ● ■ 7/20/99 7/15/99 7/6/99 ● ❍ ■ 6/29/99 ● ❍ ■ 6/22/99 ● ❍ ■ 6/15/99 ❍ ● ■ 6/9/99 ❍ ● ■ ● ❍ ■ ● ❍ ■ ❍ 8/2/99 ■ 0 ■ ■ 10 6/4/99 Total number in all plots Stink bug development in tomato research field Stink Bug Insecticide Trials » 5 trials: • 1996 & 1997, Hillsboro • 1998, Columbus • 1999 & 2000, Fremont » Products tested: • Penncap-M [lost after ‘99] • Warrior • Thiodan • Baythroid • Actara [registered 2001] » All products equally effective Stink Bug Insecticide Trial, 2000 Fremont, Ohio variety = Peto 696 Treated 11 & 24 August Harvested 11 September 50 40 % damaged Warrior 3.2 oz Actara 5 oz Actara 4 oz Baythroid 2.4 oz Avaunt 3.5 oz Untreated check 30 20 10 0 Red Breaker Green Total fruit fruit fruit fruit Stink Bug Management » Scout: • weekly in July, August • examine 10 fruit at 40 locations/field » Threshold: 0.5 - 1% fruit damage (2 - 4 damaged out of 400 fruit) » Insecticides: • Thiodan • Warrior • Baythroid • (Actara) - but this use being dropped • fresh-market only: Monitor