Southeast Michigan fruit regional report – May 7, 2013

What a difference a week of warm weather makes on fruit growth in our late spring season of 2013.

Weather

With warmer temperatures than normal over the last week, tree and small fruit growth has exploded. In fact, our much later than normal spring has caught up on itself to a point of being close to seasonal norms. There was a point in early to mid-April that our season was running close to three weeks behind normal.

I continue to see and hear reports from tree fruit growers of flower bud damage in the lower parts of the tree on sweet and tart cherries. This flower bud damage was caused by cold temperatures on the morning of April 21. The length of the cold temperatures was for several hours with lows at several farms reported in the upper teens. The extent of the damage is not severe, but there was some crop loss.

Apple growers are also noticing the lack of bloom on individual branches in a tree or even entire trees. This damage was most likely not caused from this April 21 freeze event, but by a series of events that included drought and lack of care last season and some cold temperatures in the mid-winter before buds were fully hardened.

It is quite striking to me how quickly our soils have dried out in the last week. It was amazing to see how many of our soils were very wet seven days ago and have now dried out. In fact, I have made a recommendation to several strawberry growers that they consider irrigating strawberries because their soil is too dry. This quick drying occurred due to warm day and night temperatures, several windy days and very low relative humidity recorded in the last week. Growers have been busy planting, taking care of other field work and hanging pheromone disruption ties.

East Michigan growing degree day totals for March 1 to May 6

Location

GDD42

GDD45

GDD50

Commerce (Oakland)

287

219

133

Emmett (St Clair)

282

217

133

Flint (Genesee)

355

281

184

Lapeer (Lapeer)

309

241

155

Petersburg (Monroe)

337

262

159

Pigeon (Huron)

281

221

147

Romeo (Macomb)

291

224

134

 Tree fruits

Apples are at early bloom in the southern counties, full pink in the Ann Arbor, Flint and Romeo, Mich., areas, and 0.25 to 0.5 inches green in the Thumb. I expect to see bloom in apples later today (May 7) at many farms. I expect that we will have a snowball bloom this year. This will make the tough job of thinning our large apple crop even tougher.

Insect activity has just now started to pick up, but over all things remain on the quiet side. As of this morning I had my first report of oriental fruit moth trap catch and first report of European red mite egg hatch. I am seeing a few single rosy apple aphids feeding inside the flower buds. There is the typical number of redbanded leaf rollers being caught in traps with just a few larvae seen in the last few days. Obliquebanded leaf roller larvae are being found at a few orchards. Spotted tentiform leafminers are being caught in increasing numbers, just nearing threshold in just a few apple blocks. A few apple grain aphids are starting to be found.

There is an abundance of predators being seen this season, more than typical for this time of the season. This is a reflection of most apple blocks not receiving many insecticides last season due to the lack of a crop. Many apple growers are considering skipping their pink spray this season due to the lack of insect activity and the abundance of predators. If you are doing a thorough job of scouting for rosy apple aphids and not finding any, this may be a season to skip a pink spray.

We have not had an apple scab wetting event in this past week, so things have been quiet on this front. There is rainfall expected later in the week and therefore we may be back in the apple scab control business soon.

I am concerned that apple growers may be forgetting about controlling powdery mildew this season. With recent, warmer than normal temperatures, some dew in the mornings and abundance of powdery mildew last season, growers need to apply mildewcides to control it.

With bloom comes concern for fire blight and blossom blight. You can use the two models on the Enviro-weather website to monitor possible blossom blight situations and the predictive model allows you to put your own data in or create mock scenarios to help you decide how to manage fire blight during bloom. It takes about 24 hours once a blossom opens for it to be colonized by fire blight bacteria in the most ideal conditions (high temperatures). Then, rainfall or heavy dew is needed to move that bacteria into the natural openings in the flowers to cause an infection. The first of the season Apogee applications will need to be made in the king bloom to petal fall window.

Pears are at white popcorn to early bloom. Pear psylla adults continue to fly and are now laying eggs.

Peaches are at full bloom in the Flint, Mich., area. Growers are blossom thinning. Fruit bud numbers are very high this year with good winter survival following last year’s light crop.

Sweet cherries are at full bloom, coming into bloom last Friday (May 3).

Tart cherries are at full bloom, coming into bloom on Sunday (May 5).

Plums are mostly at full bloom for European types and full bloom for Japanese types, with no petal fall coming.

Small fruits

Strawberry flower trusses have now emerged from the crown and leaves continue to emerge. Leave growth and flower bud development are a bit out of sync this year with a noted lack of leaf development. A light rate of nitrogen is needed this season to encourage additional leaf growth. A few strawberry clippers continue to be seen; it is too early to control them at this time. Some strawberry growers need to irrigate as their soils have become too dry.

Raspberries are at 2 to 3 inches of new growth for summer-bearing types. Canes of fall-bearing types are about 4 to 5 inches in length, finally emerging in good numbers.

Blueberries are at early pink bud.

Grapes are at bud swell; they have been very slow to develop this season.