SW Michigan Fruit Update
Check the Index for earlier postings
Southwest Michigan, July 29, 2008
Weather
Weather the weeks has been seasonal with highs in the 80s and lows in the 60s, with no significant rainfall.
Southwest Michigan Growing Degree Day Totals
|
Grapes, April 1 |
|||
Location |
GDD 42 |
GDD 45 |
GDD 50 |
GDD 50 |
2385 |
2057 |
1563 |
1553 |
|
2292 |
1974 |
1494 |
1486 |
|
2257 |
1944 |
1468 |
1462 |
|
2278 |
1963 |
1488 |
1481 |
|
2166 |
1855 |
1387 |
1383 |
|
2362 |
2037 |
1539 |
1534 |
|
2394 |
2100 |
1579 |
1573 |
|
2164 |
1857 |
1389 |
1382 |
|
2097 |
1790 |
1326 |
1322 |
|
Tree fruit
Leaf sampling for nutrient analysis is done in Southern Michigan, from the end of July to early August. We are seeing continued new damage due to San Jose crawlers. We are seeing this pest in more orchards this year. Mite numbers continue to increase. Japanese beetles are still active. Pheromone dispensers in insect traps need to be changed for many of the common types used.
Apricot harvest is winding down. Quality is generally good with little brown rot problems.
Peach fruit are about 2.5 inches in diameter. Some young peach plantings have red hued leaves of nitrogen deficiency brought on by excess rain. Harvest of PF-1 and Queencrest began approximately July 9; PF5B started July 15 followed by Harrow Diamond and Early Star. Harvest of Bright Star begins later this week. The estimated start of significant commercial Red Haven peach harvest for Berrien County is August 6, according to a degree-day model by Bill Shane. Leaf loss due to bacterial spot continues on very susceptible varieties such as Babygold 5 and Suncrest peaches and Flavortop nectarines. Stinkbug puncture wounds to fruit will become more obvious as the current cohort of these bugs mature. Watch for western flower thrip damage to peach and nectarine fruit when hot weather returns. Delegate offers a new option for thrip control. Oriental fruit moth adult catches continue to be high for the second generation. Growers should consider the need for control measures against larvae of this generation. Oriental Fruit Moth pheromone disruption dispensers may need to be replaced. Trunk spraying for peach tree borers is nearly done.
Tart Cherry harvesting is ended with Balaton harvest for wineries.
Plum varieties being harvested are Early Magic with Shiro at the end of week. Growers should scout for apple maggot, white apple and potato leafhoppers.
Apples are 2.2 to 3 inches in diameter. Fire blight infections are still moving and growers report lots of oozing from cankers. Streptomycin is recommended following severe storms in the summertime but there is no good material where strep resistance is a problem. Sooty blotch and flyspeck fungicides should be included in cover sprays. Trap catch for codling moth is up in some orchards indicating the beginning of the second-generation flight. Few codling moth larvae can be found in the fruit. Small numbers of Apple maggots have been caught for several weeks in SW Michigan. Apple maggot emerges following rain, about ¼ of an inch is considered the trigger amount. Obliquebanded leafroller larvae are becoming easier to find but still feeding mainly on leaves for now. The new insecticides Delegate and Altacor seem to be doing a good job controlling this insect. Spotted tentiform leafminer trap catches are declining and new mines can be found. Green apple aphids are common in growing shoot tips. White apple leafhopper leaf stippling can be found in some orchards but is generally scarce. Leaf bronzing due to European red mites and apple rust mites is easier to find. San Jose scale adult trap catch is very low and red spots on apple fruit due to crawlers are showing up in a few orchards. Young trees should be examined for potato leafhopper. Dogwood borer moth began emerging in mid June, indicating the need for trunk sprays in orchards with burr knots attractive to the insect. .
Pears are about 2 inches in diameter. Pear psylla numbers are generally low. Sooty blotch and flyspeck are a concern; fungicides should be included in cover sprays. Both codling moth and oriental fruit moth can damage pear fruit at this time.
Small fruit
Blueberry harvest of all midseason varieties is underway with heavy harvest volumes. Many growers are handpicking large volumes for the fresh market because of low process fruit prices. Japanese beetles and blueberry maggot flies are out. Preharvest sprays primarily target the diseases alternaria and anthracnose, as well as Japanese beetle and blueberry maggot.
Grapes are at nearing veraison and some early varieties have begun to change color. Grape berry moth trap catches are up indicating the start of the second generation. Larval stings and split berries are easy to find in vineyards with light crop and minimum sprays. Grape leafhoppers are scarce. Wine grapes need to be protected from potato leafhoppers. Japanese beetles are easy to find. Fungicides at this time should target all four major fruit diseases; powdery mildew, downy mildew, black rot and phomopsis. Black rot berry symptoms have been found in unsprayed vineyards as well as downy mildew. Berry susceptibility decreases as veraison begins. Phomopsis lesions in the fruit clusters can be found. The fruit becomes resistant but the cluster rachis is always susceptible to this disease. With the frequent heavy rains recently we expect significant losses to this disease.
Strawberry regrowth is underway from renovation. Growers should protect against potato leafhoppers to prevent hopper burn and stunting of new growth.
Raspberry and Blackberry harvest is continues. Growers should be prepared to protect against Japanese beetles.
Cranberries are at pinhead and small green fruit.
Upcoming Meetings
The next Monday Fruit Update meeting will be on Monday August 4, at the Fruit Acres Farm in Berrien County. The last two meetings of the season are on a biweekly schedule.
