East Michigan fruit update – May 23, 2017
Print
EmailThe extent of frost and freeze damage in apples is more extensive than most growers anticipated. Sorting out frost damage from lack of pollination is a challenge this season.
Weather
Warmer temperatures over the last week have resulted in our fruit crops growing rapidly, pushing our season ahead of normal again. This flip-flopping season has been a tough one for fruit growers. Besides the warm to cold and back to warm temperatures this spring, the windy conditions have made spraying very difficult. Our season has moved back to being a few days ahead of normal in terms of growing degree-day totals and growth stages.
Most of our region has received around an inch of rain over the last week, mostly from nighttime thunderstorms that moved through the region over the weekend. Soils south of the I-94 corridor are dryer than the rest of the region.
|
East Michigan growing degree day totals for March 1 to May 23, 2017 | |||
|---|---|---|---|
|
Location |
GDD42 |
GDD45 |
GDD50 |
|
Commerce (Oakland County) |
623 |
484 |
302 |
|
Deerfield (Monroe County) |
782 |
620 |
401 |
|
Emmett (St Clair County) |
578 |
445 |
276 |
|
Flint (Genesee County) |
708 |
560 |
362 |
|
Freeland (Saginaw County) |
604 |
473 |
304 |
|
Lapeer (Lapeer County) |
656 |
519 |
339 |
|
Pigeon (Huron County) |
508 |
387 |
241 |
|
Romeo (Macomb County) |
636 |
494 |
309 |
Tree fruits
Apples are 14 to 18 millimeters in the southern parts of the region and 10 to 12 millimeters for most other apple growers. For the second week in a row I am reporting there is still some bloom on 1-year-wood and ragtag bloom in many apple varieties, causing a concern for possible fire blight infection if the right set of rain and warmth comes.
More reports have been received of frost and freeze damage in apples from the May 8 and 9 cold temperatures. Many apple growers had significant amount of crop loss, with less amounts of damage for growers south of the I-94 corridor. The range of crop loss is as high as 80 percent, with most growers who saw damage in the range of a 30 to 40 percent loss. A few growers still have a full apple crop.
It is very hard to sort out loss to cold from lack of pollination. While we had one of the longest bloom periods ever in apples, most growers had very poor pollination conditions during that time. I estimate most of the crop loss was from frost damage with the poor pollination being a contributing factor. There are also fair amounts of apples with frost rings.
Due to crop loss, the need for extensive thinning has been greatly reduced. However, many blocks on good sites or close to wind machines have too much crop on them, and thinning is taking place this week. Consult the new carbohydrate model on our Michigan State University Enviroweather website to help make your thinning decisions. You will need to click on the fruit tab at the top of the website, then to the Apple Carbohydrate Thinning tab on the left side.
The new insect pests to report this week in apples are woolly apple aphids and European red mites. While not new, very high trap catch is being seen for codling moth and oriental fruit moth. Woolly apple aphids are just starting to be seen in low numbers in pruning scars.
A few European red mite adults and eggs are being seen, all in blocks that had high numbers last season. Very high (30 to 70) codling moth trap catch is being seen in non-mating disrupted blocks, with just a few being trapped in mating disrupted blocks. Good numbers of oriental fruit moths are also being caught in traps, mostly in non-mating disruption blocks. While plum curculio adults were reported last week, I have yet to find any fruit stinging.
Rosy apple aphids are still around, but predators have taken them out in most blocks. A few obliquebanded leaf roller larvae, green apple aphids and tarnished plant bug adults continue to be seen. Beneficials continue to be found, but their numbers are generally lower than most years.
Powdery mildew symptoms on apple leaves are a new disease to report this week. Apple scab leaf lesions were first reported two weeks ago at a few farms, but until yesterday, May 22, new lesions have been hard to find. Now they are more common. Spore discharge continues with each rain event. While the apple scab model shows that spores are mature, we still need a few more rain events for the remaining spores to be released. This might occur in the next few days, as rain is forecast.
As discussed earlier in this report, with bloom continuing in apples, growers need to be concerned about fire blight infections, especially where fire blight was a problem last season. Consult the MSU Enviroweather website MaryBlyt prediction model to determine fire blight infection events.
Pears are mostly 9 millimeters in size, with much damage reported in many pear blocks where the little fruit that remains is scarred with frost marks and rings. All stages of pear psylla continue to be found.
Peaches are all out of the shuck, with most being 10 to 12 millimeters in size. Amazingly, I have not seen much frost or freeze damage in peaches; most growers have a good crop. Green peach aphids are a new pest to report week, however their numbers are very low. Oriental fruit moth trap catch continues to be found in high numbers in most non-mating disrupted blocks.
Sweet cherries are 11 to 12 millimeters, with most of the smaller sized fruit that I reported last week starting to turn yellow with signs of it dropping off. We are not yet at pit hardening. Most growers have a nice crop of sweet cherries this season. Flower thrips are a new pest to report this week, however their numbers are very low.
Tart cherries are mostly 7 to 8 millimeters in size. We are not yet at pit hardening. Most growers report they have a good tart cherry crop this season.
Plums are at 6 to 8 millimeters for European types and Japanese types are 8 to 10 millimeters in size. Some Japanese varieties have little to no crop on them this season.
Small fruits
Grapes are between 2 and 10 inches of new growth with flower buds just starting to expand.
Strawberries are thimble-sized to slightly larger fruit for growers in the southern parts of the region and in full bloom as we move north. I think most growers in the southern parts of the region are nine to 11 days from first harvest, but if we get more warming it could be sooner.
After reading my comments in last week’s report, I have had many calls, texts and emails from strawberry growers sharing they also have poor plant growth this season. I feel this is mostly due to cold temperatures and cooler than normal soil temperatures.
Leaves have poor growth and flowers are small in size and vigor. I expect that with warmer temperatures predicted over the next week, strawberry fields will look better. Most fields need a small amount of nitrogen to help bring them around. Even with this application, leaves may not look normal through harvest.
I had one report last week of angular leaf spot symptoms in light amounts at one farm. Now is the time to be on the lookout for it.
Raspberry leaves continue to emerge on summer bearing raspberries, with first flowers on early fruiting varieties. Fall raspberry varieties are just now starting to have better growth after been frosted and burning back in the May 8 and 9 freezes. The longest canes are about 6 to 8 inches in length.
Blueberries are at early petal fall for early flowering varieties and full bloom on Jersey and mid-season varieties. Overall, we have a good amount of bloom in blueberries this season. I have not found any signs of mummy berry mummies on the ground.
