MSU Extension

Weather

This year’s cool and late spring will be one that fruit growers will remember for many years. Thus far I think that the best way I can describe our season is one of a rollercoaster ride with many ups and downs where fruit growth development surges ahead quickly and then comes to a grinding halt. As I look ahead at fruit crop development in the next week I believe that we will move ahead fairly quickly even though our daytime temperatures won’t necessarily be that warm.

Our season is still running about a week behind normal as I look at our fruit crop growth stages and development and about 10 days behind normal as I look at degree day totals across the region.

One of the most challenging aspects of the season has been for apple growers trying to control apple scab with many rain events that we have had, wet soils and windy conditions that have made it difficult to make timely fungicide applications to control scab.

Our soils are finally drying out at many farms across the region to a point where soil can be worked for the first time of the season. At those farms able to work ground, growers are anticipating planting tree and small fruits later in the week if rain holds off.

Growers are steadily working away at pruning stone fruits. Pheromone disruption dispensaries are being applied in many blocks of apples and stone fruits. As indicated earlier, growers are working hard to get planting done fairly quickly.

Tree fruits

Apples in the Flint area are at tight cluster for Idareds with most varieties at half inch green. Northern Spys are just at bud swell. In areas to the south most apples are at tight cluster, and further north most are at mouse ear or approaching half inch green. While our fruit bud development has been slow overall this spring, I’ve seen apple fruit buds move along fairly quickly in the last week.

Insect activity is beginning to pick up in apples. I am seeing a good number of redbanded leafroller adults being caught in traps, with most being in the range of 50 to 60 per trap. Spotted tentiform leafminer numbers are beginning to rise. Their trap catch numbers are about typical for this stage of growth, with most traps having between 100 and 200 adults per trap. I have not seen any oriental fruit moth trap catch as of yet. I saw my first fruit tree leafroller larvae for the season as well as my first tarnished plant bug injured flower bud. I also saw my first adult European red mite. For the most part mite numbers are low and there are not many eggs in most blocks. I am just starting to see some stethorus feeding on mites as well as a few ladybird beetles that seem to be moving around. Growers should also be scouting now for scale populations for both San Jose scale and lecanium scale.

Several growers have had continued challenges with apple scab rain events. Some of our weather stations have had three wetting events over the last week with most having one heavy infection period. Most reporting stations have had three to four infection periods for the season, while others have just had their first infection event. Apple scab leaf symptoms are expected to begin to show up over this coming weekend and early next week. We continue to collect low numbers of apple scab spores with each wetting event. Growers seem to be doing an excellent job of keeping on top of apple scab control early this season.

Pears are at green cluster for the most part. Pear psylla adults continue to fly and as of yesterday I saw my first egg hatch of pear psylla.

Peaches are mostly at quarter inch green to pink. We have no reports of oriental fruit moth catch as of yet. As indicated earlier, growers are beginning to prune peaches.

Sweet cherries are mostly at white bud to very few early varieties at early or first bloom. We have a good number of buds on sweet cherries this year.

Tart cherries are at early white bud.

Plums are at green cluster for European types and a white bud for oriental plums.

Small fruits

Strawberry leaves continue to emerge from the crown. Our strawberry rows have filled out quite nicely over the last week and are looking more toward normal. I have not seen any flower trusses emerge. Where angular leaf spot was an issue last year, growers need to consider copper applications at this time.

Raspberry leaves continue to emerge for summer bearing raspberries, and new canes continue to emerge from the ground for fall bearing raspberries. Winter damage to the tips of summer red and black raspberries is becoming more evident.

Blueberries are at quarter inch green with a nice crop coming along. Mummyberry trumpets continue to be seen at many blueberry farms.

Grapes are at early bud swell. European grapes continue to show signs of winter injury.