Before we get into the this week's apple update I just want to let you know that I'll be on vacation next week, and will not posting. That said, make sure to go no more than 10 days between fungicide applications and call/text me if something comes up!

Luke Bryan has said, "rain is a good thing". Certainly it's tough to argue those words during extreme drought conditions. However, pathogens also find rain, and really any leaf or fruit wetting to be a "good thing". Given ideal temperatures, the Colletotrichum fungus causing Glomerella leaf spot and fruit rot needs less than 3 hours of leaf/fruit wetting for infection to occur. When we look at the Klimstra weather station in Henderson County over the past few weeks, from 5/22 - 6/2, 128 hrs of leaf wetting were reported during this period and only 2 days had few than 3 hrs of leaf wetting. In Taylorsville during this same period, there was less rainfall, but 224 leaf wetting hours. Further, a good amount of this leaf wetting occurred during the day and coincided with maximum daily temperatures. This unfortunately lead to a perfect storm for the Glomerella pathogen to cause infection.

Right now in our "Glomerella Gala" research block Glomerella leaf spot and early fruit rot symptoms are beginning to pop up in our unsprayed plots. As you see in the below photo, some of the fruit in these plots have severe early symptoms of bitter rot/Glomerella fruit rot. All this said, make sure you're on top of your fungicide sprays (7 to 10 day intervals) and that you're sprayer is calibrated.

In addition, we are also seeing early symptoms of GLS. The photos below show early symptoms of the disease on leaves. Early spots appear purple in color and may be slightly irregular in shape. No concentric rings will yet be present. Often I think this could be mistaken for phytotox or early frogeye leaf spot symptoms . Scout for early GLS in the lower canopy (overwintering spores are splashed up) and higher up in the tree where spray coverage may be subpar.

Make sure to not mistaken GLS symptoms for frogeye leaf spot (photo below on left) and apple blotch/Marssonina leaf blotch (photo below on right). With frogeye, symptoms often begin as small purple circular lesions, and then advance in more round lesions (compared to GLS) with a small dot in the lesion center (the "frogeye"). These lesions do not have concentric rings, but may grow into each other and appear similar to a GLS lesion to the untrained eye. With MLB, early symptoms are more diffuse purple spots and then advance into diffuse purple blotches. All three diseases can lead to leaf chlorosis (yellowing) and premature defoliation.

In regards to what to spray this week... You've likely been focused on GLS the past couple of weeks. 2.5-3 lb/A Captan 80WDG will be a good option; especially since it looks dry until Sunday. I would consider something extra in the tank for MLB if you've primarily been focusing on mancozeb or captan. Some strong options include Cevya (5 fl oz/A) or Inspire Super (12 fl oz/A)