2015 Fruit Pest Update

August 11, 2015

Updates for the rest of the season will be every two weeks instead of weekly.   

Cherry harvest is now over in many orchards, but  populations of spotted wing drosophila continue to rise due to the number of fruit left behind that were immature when trees were shook. We continue to monitor this pest and compare populations to past seasons in an effort to keep growers informed about risks and the need for additional controls.

APPLE

Disease Pressure – Scab infections occurred on 8/3 & 8/7 last week. This does not bode well for orchards that have lesions on leaves or fruit from primary season infections. In orchards with active lesions protectant fungicides should be applied on a tight schedule (10-14 days) to keep leaves and fruit protected prior to any new infection events. Captan continues to be the fungicide of choice when protecting fruit from secondary scab infections. If scab has not been detected, one or two more fungicide application before harvest may be all that is needed in these low pressure orchards.

Insect Pressure – Codling moth trap catches have been near zero and below threshold in most orchards. We expect trap activity to pick up in the next week or so as 2nd generation flight begins. A few high pressure orchards are still seeing moth catches above threshold (+5 moths per week). These may require continued control applications on a 10-14 day schedule. Apple maggot catches continue in all scouted orchards and fruit needs to be protected from infestation with future cover sprays. European red mite populations have begun to rise in many apple orchards, as they often do at this time of the year, as we get dryer and high temperatures reach the upper 70’s and lower 80’s. Numerous miticides are available and should be applied at higher label rates as populations have a tendency to build quickly and can be much harder to knock down at this time of the season.

CHERRY

Disease Pressure – New cherry leaf spot lesions are becoming noticeable in many scouted orchards as growers have been busy with harvest and infection periods seem to be occurring 1-2 times a week again. Post harvest fungicide applications will be extremely critical this season because of the numerous infection events and the high level of infected leaves for this time of the year. Chlorothalonil containing products (Bravo, Echo Equus, etc.) are the best choice for post harvest control applications. Copper fungicides may also be considered where infection is high and a second post harvest application is needed. It would be best to use the copper compounds in a second application 3-4 weeks after chlorolthalonil when temperature are not has warm to avoid phytotoxicity.

Insect Pressure –  Cherry fruit fly and spotted wing drosophila (SWD) continue to be caught  on the peninsula. The level of SWD catches are increasing in many orchards post harvest, as there is an abundance of immature fruit still on the trees. It is thought that this build up to high levels after harvest may be what is contributing to the earlier emergence of this pest and the greater likelihood of finding their larva in the fruit in the tank .

 
 
 
 
 Spotted Wing drosophila
Trade Name
PHI
 Cherry Fruit Fly Control
Control Rating
0-3 days
Control Rating
7-14 days
Sevin
1 Day
Good
3
4
Malathion
1 Day
Good
1
3
Danitol
3 Days
Good
2
2
Imidan
7 Days
Excellent
2
2
Delegate
7 Days
Good
2
2
Spintor
7 Days
Good
2
2
Warrior 14 Days Good 2 2
Control Rating Key: 1=Excellent (90%+), 2= Moderate (90-60%), 3=Low (60-30%), 4=Poor (30-0%)

GRAPE

Disease Pressure – Grape berries are no longer susceptible to fruit infections of powdery mildew, downy mildew, black rot and phomopsis. However growers should apply a botrytis fungicide before bunch closure to reduce late-season fruit rots. Symptoms of black rot leaf infection have been on the rise in a few of the more susceptible varieties. The recent wetting events coupled with warmer temperatures has led to a number of black rot infection periods in the last week (8/3 & 8/7). The increase in humid weather is also leading to the development of powdery mildew on susceptible varieties.

Insect Pressure – Grape growers with a history of grape berry moth should scout carefully for the presence of eggs on berries and cluster stems as second generation grape berry moth are hatching.

Links to individual Enviro-Weather stations:

Casco   Southern Door   Sturgeon Bay   Egg Harbor   W Jacksonport   Sister Bay