This disease does not typically affect Indiana tomatoes, instead preferring tomatoes grown in tropical and sub-tropical areas. Since Cercospora leaf mold was observed in two different areas of Indiana in the 2015 season, it makes sense for growers to become aware of this disease in case it returns to Indiana in 2016. The two locations…Read more about Cercospora Leaf Mold of Tomato[Read More]
Plant Disease Management
Late in the 2015 season, I observed some unusual symptoms of anthracnose on watermelon fruit. I wanted to discuss these symptoms, but first a little background of cucurbits. An extension bulletin on this subject may be found at https://www.extension.purdue.edu/extmedia/bp/bp-180-w.pdf. Anthracnose of cucurbits, caused by Colletotrichum orbiculare, is responsible for lesions on leaves, stems and fruit. Crops affected…Read more about Symptoms of Anthracnose of Watermelon on Fruit[Read More]
In 2014 and 2015 blackleg-like symptoms were observed in some U.S. potato growing areas. The presence of a bacterium of the species Dickeya was confirmed by PCR testing. Symptoms caused from this pathogen may include leaf wilts and tuber soft rots which may extend internally up the vascular system of the stem. USDA APHIS PPQ…Read more about Blackleg-like Symptoms of Potato[Read More]
I have observed this disease in several pumpkin fields this year. It is not clear to me why this disease seems to be more widespread compared to recent seasons. However, it makes sense to review Plectosporium blight here. Plectosporium blight is usually not a serious disease. The occurrence of this disease is usually sporadic. However, when…Read more about Plectosporium Blight[Read More]
The relatively cool weather Indiana has experienced this summer may be responsible for more observations of northern corn leaf blight (NCLB) on sweet corn than normal. The primary symptom is the cigar shaped lesion that ranges from 1 to 7 inches in length (see Figure 1). The lesions may range from tan to gray in color….Read more about Northern Corn Leaf Blight[Read More]
When used as a verb, to rogue means to get rid of items that don’t conform to a certain standard. In plant pathology, the word rogue is used to describe a technique whereby diseased plants are removed or rogued to slow the spread of disease. I’d like to describe the practice as it might be used…Read more about Roguing as a Tool to Manage Phytophthora Blight of Pumpkin[Read More]
Downy mildew has been confirmed on jack-o-lantern pumpkins in Daviess and Jasper Counties and on acorn squash in LaPorte County. These are the first confirmed reports of this disease on Cucurbita pepo in Indiana in the 2015 season. There are unconfirmed (but reliable) reports of downy mildew on pumpkins in Parke, Washington, and White Counties. This disease has…Read more about Downy Mildew of Cucurbit Update[Read More]
This disease has been observed in northern Indiana on basil sold as a fresh herb. The fungus that causes downy mildew of basil does not overwinter in Indiana; instead, it must blow in from the south. The fungus that causes downy mildew of basil is not the same fungus that causes downy mildew of cucurbits…Read more about Downy Mildew of Basil[Read More]
Late blight has been reported on processing tomatoes in Cass County Indiana. This is a late blight update from when this disease was reported on potatoes and tomatoes in LaGrange County Indiana. The latter outbreak and some disease management tips are reported in the Vegetable Crops Hotline Issue 603 at ag.purdue.edu/hla/Extension/VegCropsHotline/Pages/Latest-Articles.aspx?article=117 This article was originally…Read more about Late Blight on Tomato Update[Read More]
On July 22, I announced that downy mildew had been observed on watermelon in Knox County in southwestern Indiana. This article in the Vegetable Crop Hotline issue 603, https://ag.purdue.edu/hla/Extension/VegCropsHotline/Pages/Latest-Articles.aspx?article=118, describes the outbreak and management options. Downy mildew has now been reported on cucumber and cantaloupe in Knox and cucumber in La Porte County Indiana and pumpkin in Jasper County….Read more about Downy Mildew Update[Read More]