I recently had the opportunity to speak with a grower who was trying to describe what pesticides had been used in his operation. This experience made me realize how confusing it can be to pick out the proper pesticide name. This article will help to describe which pesticide name to use, using fungicide as examples. [Read More…]
Dan Egel
Phytophthora blight was a serious disease this past season. As a result, I have had many questions about managing this disease. The following article is an update of a previous article on this subject. The questions I have been asked have ranged from what do I spray to how does this disease work? Therefore, I[Read More…]
This is an update of the article When to Stop Spraying Fungicide published in issue 666 on Sep. 12, 2019. Many vegetable growers are closing in on the final harvest. Several growers have asked me about fungicide applications late in the season. In this article, I want to address when to stop. To limit the[Read More…]
This disease appears to be more important each year. It is not clear to me why. This article reviews Plectosporium of pumpkin, sometimes called white speck. I would rank Plectosporium blight behind powdery mildew, bacterial leaf spot and Phytophthora blight in economic damage caused. The occurrence of this disease is usually sporadic. However, when it[Read More…]
Downy mildew was observed on pumpkins in Daviess, Knox and Washington County. Evenings and mornings with heavy dews and fogs may help the disease to spread. Whether to apply fungicides for this disease will depend in part on when growers plan to harvest. In addition to the cucurbit downy mildew outbreaks reported in the last[Read More…]
Downy mildew has been observed in LaPorte County in northern Indiana on cucumber. In addition, downy mildew on cucumber has been reported in southern Kentucky and on watermelon in the Kansas City area of Kansas. Growers in northern Indiana should manage for downy mildew on valuable cucurbit crops (Figure 1). Growers throughout the state should[Read More…]
On a sandy hillside in a watermelon field, we noted vines that, from a distance, appeared undersized compared to the vines in the flats. Upon closer inspection, some of the vines had either wilted or a portion of the plant had wilted. The wilted vines had discolored vascular tissue. These vines were affected by Fusarium[Read More…]
What is causing the spots on the watermelon leaf? A) anthracnose B) early blight C) a contact herbicide The answer is that the leaf above has been affected by a contact herbicide. The herbicide caused lesions upon contacting the leaf. However, there was no growth of the lesion and no yellowing of the leaf[Read More…]
Downy mildew has been observed on cucumber in Berrien County in extreme southwestern Michigan and in Monroe County in extreme southeast Michigan. The downy mildew spores that cause disease on cucumber will cause disease on cantaloupe and may cause disease on other cucurbits such as pumpkin and watermelon. The forecast is for the spread of[Read More…]
This disease was observed in a home garden recently on table beet (Figure 1). I was surprised considering how dry it has been. Cercospora leaf spot also affects swiss chard. Symptoms include circular leaf spots that may have a reddish margin. The center of the lesions may start off a light brown and turn to gray after the fungus (Cercospora beticola) begins to sporulate.[Read More…]