At midseason, scout fruit (20-30 apples or pear) in the interior canopy of sample trees. Signs of this disease are more obvious on light colored fruit, like Golden Delicious, Pristine, or Yellow Transparent. The disease is worse in poorly pruned trees in the wetter, foggy, slow-drying areas of the orchard. This year, in some parts[Read More…]
Disease Management
Warm, wet, summer weather, coupled with any lapses in orchard sanitation, can result in summer disease outbreaks. At Meigs, we are seeing the foliar stage of Botryosphaeria, aka frog eye leaf spot (Fig. 1). On the plus side, we won’t be surprised when we see black rot on the apples at harvest (Fig. 2). Fortunately,[Read More…]
ReTain (AVG) is a plant growth regulator that blocks the production of ethylene. When ReTain is applied to apple, several ripening processes are slowed, including preharvest drop, fruit flesh softening, starch disappearance, and red color formation. In order for ReTain to be effective it must be applied well in advance of the climacteric rise in[Read More…]
Preharvest drop refers to the process where fruit fall from the tree prior to harvest. Not all apple varieties are affected, but with some, such as McIntosh and Pristine, pre-harvest drop can be extreme. Several growth regulator materials are available to growers to help reduce pre-harvest drop. These materials are often referred to as “stop-drop”[Read More…]
We are already receiving reports of brown rot, caused by several different types of the fungus Monilinia., Many of these are causing shoot blight, but we are receiving samples of brown rot on cherry fruit. Brown rot is a common and destructive disease of stone fruit, a closely related group of trees that include peach,[Read More…]
Finally we have some warm, sunny weather, and that means fruit are growing quickly. Generally, fruit are 10–20 mm depending on where in the state you’re located. Many of our common post bloom thinners such as NAA, Sevin and Maxcell work very well when fruit are around 12mm and temperatures are in the 70s. Once[Read More…]
Fire blight seems to have established itself in many orchards throughout the state, meaning it can still be a huge threat in the event of trauma, like hail, due to secondary spread. Secondary spread develops when stormy weather, especially hailstorms, occurs after the primary (blossom) infections. The amount of fire blight that develops after severe[Read More…]
Immediate post-bloom through about 3 weeks post bloom is the most effective time for leaf removal on tight clustered varieties such as Vignoles, Seyval, and Pinot gris. That time will be coming up soon in southern Indiana. Removal of 3 to 5 leaves in the cluster zone can greatly reduce risk of Botrytis bunch rot.[Read More…]
The weather this spring has been ideal for development of Phomopsis cane and leaf spot. The past few weeks have been cool with frequent showers, and shoot growth has been slow. These conditions favor sporulation and infection by Phomopsis. This pathogen is one of the major causes of fruit rot in the Midwest. Early season[Read More…]
Although the season for primary scab infection is winding down, this cool, wet weather is making for an excellent infection period for juniper rusts (Gymnosporangium spp). John Obermeyer and I created this time-lapse video to help explain the complicated lifecycle of this fascinating pathogen: http://tinyurl.com/j3s3t92 The juniper rusts standout due to the conspicuous nature of[Read More…]