are sampled in a V-pattern as with TSM by shaking 

 2 to 4 flower clusters over white cardboard at each 

 sampling location (at least 20 flower clusters 

 should be sampled across the field). If average 

 nymph counts exceed 1 nymph per cluster, then a 

 petal-fall insecticide application should be made. Do 

 not apply insecticides during bloom. If TPB 

 have been a serious problem in the past, an early- 

 season insecticide application may be made prior to 

 10% bloom to target the egg laying adult females. 

 This treatment should be made on a sunny, warm 

 day when the insects are active. 



Controlling weeds in and around the planting 

 may reduce populations of this insect, but insecticide 

 sprays generally are necessary. Combining such 

 sprays with treatment for clipper, where necessary, 

 can save an insecticide. 



We have also started to study a potential preda- 

 tor of TPB. Peristenus digoneutis, a braconid wasp 

 parasite of the alfalfa plant bug, Lygus hirsuta, and 

 TPB, was introduced into the United States by 

 USDA entomologist Dr. William H. Day. While the 

 parasite was introduced for control of plant bug in 

 alfalfa, Dr. Day feels that it has potential for control 

 of TPB in strawberries. The parasite has been estab- 

 lished in northern New Jersey with parasitism rates 

 of TPB nymphs in an alfalfa field ranging from 50 to 

 90%. In 1990, two collection trips were made to New 

 Jersey. Parasitized TPB nymphs were released at 

 two sites in Massachusetts. Plans for 1991 include 

 more collection trips and monitoring for the estab- 

 lishment of the parasite at the previous year's re- 

 lease sites. Dr. Day estimates an establishment 

 period of 3 to 5 years. Once the parasite is estab- 

 lished, further work will need to be done to deter- 

 mine efficacy of the parasite 

 in controlling TPB in straw- 

 berries. 



with a copper-colored body and a black head with a 

 long snout. 



The female weevil chews a small hole in un- 

 opened flower buds and lays an egg in the hole. She 

 then girdles the stem just below the bud. The flower 

 bud dries up and dangles from the stem, eventually 

 falling to the ground. The immature weevils, or 

 grubs, develop in the girdled buds, emerging as 

 adults in the early summer, and then migrating to 

 wooded areas. 



Scouting for clipper. These insects are not al- 

 ways present and may only cause minimal damage 

 some years. Examine the plants before bloom for 

 clipped buds. As with TSM sampling, a V-shaped 

 transect should be made in the field with 5 to 10 sam- 

 pling locations. A 2-foot section of row should be 

 examined at each location. A samplingframe may be 

 made for this purpose. If an average of 0.6 clipped 

 buds per foot of row is reached, control measures 

 must be taken. As mentioned above, Lorsban should 

 be avoided if TSM are a problem. 



Impact of the Strawberry IPM Program 



Ten cooperating growers were enrolled in the 

 program in 1990, as compared to 16 growers in 1989. 

 This decrease was due to a decreased operating 

 budget from 1989 levels, requiring us to drop some of 

 the smaller growers or those isolated from other 

 growers. However, 48 acres were scouted by the 

 program in 1990 (only three acres less than in 1989) 

 with an additional 51 acres scouted privately under 

 our supervision. Together this total represents ap- 

 proximately 20% of the commercial acreage in the 

 Massachusetts. 



Under IPM recommendations, cooperating 



Strawberry Bud Wee- 

 vil ("Clipper") IPM 



This insect can build up 

 quickly, so the action 

 threshold is relatively low. 

 The sampling procedure can 

 miss rapid build-up of the 

 pest if done on a weekly 

 basis. This insect occurs 

 somewhat less frequently 

 than tarnished plant bug 

 but causes economic injury 

 where it does occur. The 

 insect is a very small beetle 



Fruit Notes, Spring, 1991 



