SW Michigan Fruit Update
May 23, 2006
Weather
Last week generally cool, with highs in the 50s and 60s with lows above 40 at night. Growing Degree Day accumulations have slowed and we are near normal. Rain fell Monday and Wednesday, 0.3 inches of rain. This long cold period slowed plant growth and insect and disease activity. Soils are moist. Soil temps are in the low 50s. Scattered frosts Monday morning caused little damage. This week’s forecast is for much warmer weather with highs into the 80s by the weekend. The GDD below are from the Enviroweather site.
Southwest Michigan Growing Degree Day Totals March 1 through May 21, 2006 |
Grapes, April 1 |
|||
Location |
GDD 42 |
GDD 45 |
GDD 50 |
GDD 50 |
674 |
529 |
332 |
302 |
|
666 |
511 |
309 |
277 |
|
698 |
540 |
332 |
298 |
|
603 |
461 |
276 |
249 |
|
701 |
546 |
340 |
314 |
|
South Haven (April 1) |
475 |
368 |
226 |
226 |
698 |
544 |
342 |
305 |
|
597 |
453 |
269 |
241 |
|
Tree Fruit
The warm temperatures should bring on a lot of insect activity. Tarnished plant bug and plum curculio will be a problem when it warms up and controls should be applied before Thursday. Growers report large numbers of ladybug adults, larvae and eggs in orchards. San Jose scale has become a problem in the area and growers should be aware that the first flight should begin soon.
Apricot fruit are about one inch in diameter.
Peaches are at 10 mm. Foliage is off-color and growing slowly due to recent cool weather. A few orchards have been hand thinned but most will be done when fruit are larger. A lot of fruit have self-thinned but the crop is still decent in many orchards. Oriental fruit moth trap catches are low. We should be at peak adult emergence but cool temperatures have kept the flight down. We set Biofix Oriental fruit moth as April 16 with a GDD of 180 Base 45 at SWMREC. Chemical controls are focused on egg hatch, which continues to about 650 GDD after biofix. We are about 331 GDD past Biofix. Tarnished plant bugs have been found in peach orchards and growers are mowing orchards. This can drive the bugs into the tree canopy to feed on the fruit. We are starting to catch lesser peach tree borer.
Sweet cherries are 14 mm fruit and nearing the end of pit hardening. Plum curculio will be a problem when it warms up.
Tart cherries are at 10 mm fruit and relatively uniform in size. The crop looks a little heavier than average. Growers need to protect against cherry leaf spot. No cherry leaf spot symptoms have been found yet. In general the weather has been too cool for this disease. There is some shot holing of the leaves probably from bacterial canker but not other symptoms have been found.
Plums are at 10 mm fruit and the fruit is starting to sort out by size. We will not have a good estimate of the crop for several weeks. Growers need to protect against plum curculio and to maintain protection for black knot.
Apple fruit set is good. The fruit are about 10 mm
in diameter. The warm temperatures forecast
for later this week are an ideal thinning window with temperatures rising from the 50s
into the 80s by the weekend apply thinners when daytime highs are forecast to be above 70. Growers need to protect against plum curculio. Wednesday’s rain was an apple scab infection
in some areas. Scab symptoms from earlier
rains have been found. Scab symptoms from
infection periods in early May should be appearing now.
Scab spore release has continued at low levels.
We have not reached the end of primary scab. You can monitor scab spore maturity using the Enviroweather
site. Growers need to maintain scab protection.
Growers also need to protect against powdery mildew.
Fire blight canker
margin symptoms should appear this week as wilted shoots near old cankers. Fire blight could be a problem if
we get severe weather in orchards with oozing cankers and shoots. Cool
weather kept oriental fruit moth
and codling moths trap counts
low last week. A regional biofix for codling moth has not been set. We expect the flight to begin again with warm dry
weather this week. See the article on pesticides for codling moth in
last week’s Fruit CAT Alert. Leafroller
larvae about 20 mm long can be found in apples. Obliquebanded leafroller traps
should be out. Other regions are report high
numbers of European red mites
in some areas so growers should scout their hot spots.
Pear fruit are at 10 mm. Growers need to protect against pear scab. Pear psylla nymphs are common in some orchards. Pear blister mite was reported for several small growers.
Small fruit
Blueberries are blooming. Growers should be protecting against mummy berry and anthracnose fruit rots. Few mummy berry shoot strikes have been found. Cherry fruitworm are being caught in pheromone traps. We expect to see cranberry fruit worm emergence this week with the warm temperatures. See the article on these fruitworms in last week’s Fruit CAT Alert. Growers should be ready to treat for these pests at the end of bloom. Post bloom sprays also control blueberry gall midge and blueberry tip borer.
In Grapes, primary shoots are almost a foot long
and secondary and tertiary buds are opening. New
growth is off-color and growing slowly due to the cool weather. There are few live secondary buds. In areas showing little growth from a distance
both primary and secondary buds are dead. An
accurate estimate can made when flower clusters in new replacement shoots are visible. Growers should continue their disease control
programs in areas that show fair growth and may have a marketable crop. Grape flea beetle larvae have been found feeding
on the leaves.
Strawberries are blooming. The cool, wet conditions have been favorable for Botrytis grey mold disease development.
Raspberries flower clusters are emerging. Growers should be scouting for leafrollers.
Cranberry buds are beginning to burst.
Miscellaneous
Many growers mowing cover crops to allow better movement through the orchards.
There will be no Monday Fruit IPM meeting on May 29. The next Monday Fruit Update meeting will be, Monday June 5, at the Fruit Acres Farm in Berrien County, at 5 PM.
The Grape IPM meetings in Berrien and Van Buren Counties on Thursday, May 25 will discuss management options for freeze-damaged vineyards. The morning meeting will be from 10 AM to noon at the Cronenwett Farm Shop at 70123 28th Street east of Lawton. The afternoon meeting will be at the Southwest Michigan Research & Extension Center from 2 to 4 PM.
A series of twilight grape scouting IPM meeting will start in June. The dates and locations are; June 15 at Tim Seppala's farm, east of Lawton; July 20 at Bob Dongvillo's farm, south of Benton Harbor; and August 17 at Lemon Creek Vineyards, Berrien Springs.
