LEXINGTON, Ky. — The heat units necessary for fruit crop development have accumulated very rapidly as reported in the March-April Fruit Facts and our fruit crops continue to develop well ahead of schedule. Figure 1 shows Lexington heat unit accumulations expressed as Growing Degree Days for 2017 in comparison with a number of previous years. This chart shows how fortunate we were in avoiding a severe spring frost and drastic fruit crop losses (2007, 2012, and 2015). As of July 6 plant development is running about two weeks earlier than normal. This translates into earlier harvests, but it also means that some pests are showing up considerably earlier than normal.
This is particularly true for Japanese beetles and Spotted wing drosophila (SWD). Soil moisture from June through August greatly affects the capability Japanese beetles to emerge, lay eggs and for the eggs to survive. The wet spring and summer the last three seasons has led to high Japanese beetle numbers in some areas and this has taken some growers by surprise. Spotted wing drosophila trap catches have occurred particularly early this year and the mild winter allowed many more than normal to winter over. This has resulted in very high levels of egg laying. Some blackberry and blueberry growers have already been alarmed to find high populations of worms in their fruit.
This is not good for consumer confidence in Kentucky produce and can ruin our market. Many blueberry growers have not sprayed for SWD in the past, but this year may be an exception. Test for SWD in your fruit before taking them to market. Weekly preventative sprays are necessary for blackberry production and may be necessary for blueberry producers this season once this pest is trapped because of excessive numbers of SWD. Backyard growers may cover their plants with a fine meshed netting to avoid spraying. See the article by Ric Bessin on SWD that follows.
Apple growers have generally been feeling pretty good about the crop so far. Expected fire blight infections based on high chances of infection throughout bloom generally resulted in few infections. Most other pests with the exception of Japanese beetles and Cedar apple rust have been at normal levels. I have notices an outbreak of Woolly apple aphids in our university orchard (see photo in masthead) here in Lexington and we have sprayed for them with Movento (PHI 7 days). I am a little perplexed by this buildup since we did not spray any synthetic pyrethroid sprays last or this season which kills Woolly apple aphid natural predators.
The peach harvest and early apple harvest are going well. Peaches are in high demand due to a tremendous crop loss in Georgia and South Carolina caused by a lack of winter chilling and spring freezes.
The strawberry crop this year was a difficult one for growers. Many plasticulture growers that planted on time ended up with larger than normal plants with too many branch crowns due to the mild winter. This resulted in smaller than normal fruit. Excessive rainfall made harvest difficult and drastically increased fruit decay problems after harvest. Many matted row strawberry growers also had problems with excessive rain, U-Pick customer turnout, and smaller than normal fruit size. As a result some fruit did not get harvested.
— John Strang, U.K. Extension Horticulturist, Ric Bessen, U.K. Extension Entomologist, and Matt Dixon, U.K. Ag Meteorologist
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