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…]
Disease Management
Grapes in the southern half of the state will soon be reaching the critical pre-bloom stage, which is a key time to control important diseases such as black rot, downy mildew, and powdery mildew. The next three or four sprays will be critical in controlling fruit infections. Growers should pay extra attention to getting thorough[Read More…]
Fire blight, caused by the bacterium Erwinia amylovora, is a devastating disease of apples and pears. Epidemics of the disease develop quickly, particularly in a climate of warm, wet weather, with hail events—like last night’s 0.75” to 1.5” hail! The type of management program developed by each orchard will vary considerably based upon a variety[Read More…]
We’re getting close to the time when growers need to make chemical thinning decisions – for many the most perplexing and risky decision they will make all year. This is usually a tricky call to make, even more so when we have had spring frosts. Luckily in most places the spring frosts have not been[Read More…]
Grape growth is a bit ahead of normal this year. Grapes are at the critical 1 to 3 inch shoot length when Phomopsis cane and leaf spot infections occur. This is a critical time to take control measures for this disease. If left unchecked, the early shoot infections will spread to cluster stems and developing[Read More…]
Weather for 2016 continues to be unpredictable. And although bad weather can damage crops, it does little to stop the pathogens that plague pome fruit. The past few weeks of cool weather has slowed things down, but not scab—at least, not completely. All plants, insects, and pathogens develop in response to temperature–The warmer the weather,[Read More…]
The 2016 Midwest Fruit Pest Management Guide (ID-465) is available for purchase from the Purdue Education Store. This publication replaces two previous annual publications: The Midwest Tree Fruit Spray Guide (ID-168) and The Midwest Small Fruit and Grape Spray Guide (ID-169). This guide provides pest management recommendations for commercial tree fruit, small fruit, and grape[Read More…]
Ascospore release is timed to optimize infection, which happens around tight cluster through petal fall. This is when all the fun really begins: Ascospores are at their peak and ejecting, and apple tissue is expanding, providing a larger, susceptible canopy that spores can hit. That excellent timing is the poetry of evolution in motion. Other[Read More…]
A black swan refers to an event that defies expectation and that would be extremely difficult to predict. This spring is one of those. And although it seems unlikely that we will emerge from our last frost-free date (May 15 here in Tippecanoe County) unscathed, it could happen and then you could end up with[Read More…]
The most important spray of the season for control of anthracnose on brambles is the delayed dormant spray of lime sulfur, Sulforix or copper hydroxide. If you have a problem with anthracnose, this is one spray that you can’t afford to miss. One of these materials should be applied when new leaves are exposed 1/4[Read More…]