Plant Disease Management


​Protecting vegetable crops from foliar disease involves many factors. Crop rotation and fall tillage will help to lessen disease severity. Choosing a resistant or partially resistant variety can lower the amount of disease. Purchasing seed that has been tested for seed borne disease is also an important factor. Most growers, however, find it is also…Read more about To Spray or Not To Spray[Read More]


​Tomato growers who utilize high tunnels to reach early markets often find that there are few economic alternatives to tomato. Therefore, many growers grow tomatoes after tomatoes instead of rotating to a different crop. The repeated cropping of tomato in the same area can lead to disease problems such as Fusarium crown rot and white…Read more about Soil Solarization[Read More]


​Late blight has been reported on potatoes and tomatoes in LaGrange County.Potato and tomato growers in northern Indiana should follow the management recommendations listed below and in the Midwest Vegetable Production Guide for Commercial Growers 2015 (ID-56). Late blight thrives under cool, wet conditions. The disease can easily spread from plant to plant. Under ideal…Read more about Late Blight in LaGrange County[Read More]


​On July 22, I announced that downy mildew had been observed on watermelon in Knox County in southwestern Indiana. This article https://ag.purdue.edu/arp/swpap/VeggieDiseasesBlog/Lists/Posts/Post.aspx?ID=48 describes the outbreak and management options. Below, I will discuss the whereabouts of additional downy mildew outbreaks on cucurbits.  Downy mildew has now been reported on cucumber in Knox and La Porte County Indiana….Read more about Downy Mildew Update[Read More]


​Gray mold of tomato is one of the more common diseases of greenhouse-produced tomatoes. Although it is often a minor problem, if left unchecked, gray mold can cause yield loss. Gray mold, or more properly, Botrytis gray mold, often causes a light gray or brown necrotic lesion on leaves (Figure 1). The lesions on leaves are sometimes…Read more about Botrytis Gray Mold of Tomato[Read More]


This disease has been observed on watermelon in Knox County. The following article will discuss the symptoms, biology and management of downy mildew of cucurbits. Symptoms. The symptoms of downy mildew vary depending on the host.    On watermelon, the lesions start out as chlorotic (yellow) areas that become round and necrotic (brown/black) areas surrounded by…Read more about Downy Mildew of Watermelon[Read More]


​This disease has been reported near West Lafayette and in Wanatah Indiana. Powdery mildew of tomato can be recognized by the white fungal colonies on both leaf surfaces (Figure 1). Occasionally, stems may also be infected. Severely affected tomato plants may have leaves that turn chlorotic and necrotic. Fruit will not be directly affected. The causal organism has been…Read more about Powdery Mildew of Tomato[Read More]


​I have observed many fields of cantaloupes with magnesium deficiency or manganese toxicity. Watermelon plants may exhibit similar symptoms, but not as frequently as cantaloupe. Both disorders are related to acid (low pH) soils and usually occur in clusters in a field. Magnesium deficiency usually appears on sandy ridges and can be recognized by interveinal…Read more about Magnesium and Manganese in Melon[Read More]


​Burrs and Cones. Both of the trellises in the Boiler Hopyard have begun flowering and coning. The primary shoots were pruned at the top of the net on the dwarf trellis in order to promote lateral growth. The pruning took place on May 19 and again on May 28. The bines on the dwarf trellis…Read more about Boiler Hopyard Update-July 9, 2015[Read More]


​Most growers first notice this disease when large, soft areas develop on mature watermelon fruit. These lesions can be several inches across and are often covered with a white mold. The lesions usually form first on the bottom of the fruit, close to where the fruit comes into contact with the soil. Further development of the…Read more about Phytophthora Fruit Rot of Watermelon[Read More]


Page last modified: February 8, 2016

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