downy mildew cucumber

Fungicides are effective if applied before disease becomes severe. Plant resistant varieties when available. MSU is an affirmative-action, equal-opportunity employer, committed to achieving excellence through a diverse workforce and inclusive culture that encourages all people to reach their full potential. This article was published by Michigan State University Extension. Also, keeping an eye on the spore trap results across the state could be helpful in knowing when the cucumber downy mildew pathogen has been found in your particular production region. Updated July 2020. On members of the cucumber family (cucurbits): important on cucumber, rockmelon and zucchini, but also on gourd, melon, pumpkin, … For downy mildew to occur in Minnesota, air currents must blow the spores. Our spore trapping network detected downy mildew spores from Berrien County for three days last week but we did not find diseased plants in nearby cucumber fields until today, June 22. This information is for educational purposes only. However, downy mildew has arrived in the Midwest earlier in the season. Extension is expanding its online education and resources to adapt to COVID-19 restrictions. Our spore trap webpage is updated with the latest results on Thursday morning of each week. Downy mildew can infect all cucurbits including cucumber, melon, pumpkin and squash. The warm and humid weather conditions this month favors downy mildew. The pathogen can move on air currents, splashing water and on the tools and hands of workers. Use drip irrigation and wide row spacing to dry the leaves and encourage good air movement around the plants. University of Minnesota Extension discovers science-based solutions, delivers practical education, and engages Minnesotans to build a better future. Cucurbit downy mildew in a cucumber field with many necrotic and chlorotic lesions. On watermelons, an exaggerated upward leaf curling is common. Because downy mildew doesn’t survive the winter, the pathogen must re-emerge each growing season. This is most distinct in cucumber. Note: Cantaloupe crops are also at risk of becoming infected by the downy mildew pathogen and should be protected using the fungicides that have been proven to be effective in MSU research cucumber field studies. This year’s outbreak is much ahead of 2019’s first outbreak. Occurrence varies spatially and temporally year to year with movement of this wind-dispersed pathogen. Commercially important species of cucurbits include watermelon (Citrullus lanatus), muskmelon (Cucumis melo), cucumber … To contact an expert in your area, visit https://extension.msu.edu/experts, or call 888-MSUE4MI (888-678-3464). Prior to that, it had not been effective. Growers on the west side of the state should be using this short, seven -day application interval for their fungicide sprays. 2020 It thrives in wet or very humid conditions as a water mold. © This is the first confirmation of this devastating disease in the state for 2020. Downy Mildew of Cucurbits. Downy mildew lesions on a cucumber leaf. The pathogen can move on air currents, splashing water and on the tools and hands of workers. Downy mildew can start an infection in a wide range of temperatures (41-86° F) but is most severe from 59-68° F. The pathogen needs moisture on the leaf surface in order to germinate and start a new infection. Click here for instructions on how to submit samples. Moderate to low levels of resistance are available for melons. Downy mildew on cucumber has been verified in Berrien County, which is located in southwest Michigan. However, in other years, it has been common to record the first field outbreak around the first week of July. The leaves appear as if frost had killed them. Michigan State University Extension programs and materials are open to all without regard to race, color, national origin, gender, gender identity, religion, age, height, weight, disability, political beliefs, sexual orientation, marital status, family status or veteran status. There are several strains of downy mildew that attack different crops. It is important to rotate systemic fungicides or tank mix with a contact to avoid this. We are able to distinguish between cucumber and hop downy mildew spores using molecular tools and both are reported. This is the first confirmation of this devastating disease in the state for 2020. Monitor plants for symptoms of disease, especially from August through harvest. Causal Agent. Leaf spots grow together and entire leaves turn brown. The 4-H Name and Emblem have special protections from Congress, protected by code 18 USC 707. The downy mildew pathogen is an obligate parasite that needs living cucurbit plants in order to grow and survive. Cucumber downy mildew (143) - Worldwide distribution. The University of Minnesota is an equal opportunity educator and employer. We are working with growers, scouts, consultants and MSU Extension educators to make sure we get suspect samples immediately and make a diagnosis. The cucurbit downy mildew pathogen P. cubensis results in defoliation, poor plant health, and significantly reduced fruit yields due to sun scald, reduced nutrition, and secondary rots. View the spore trap results and current downy mildew news. Check out the MSU Viticulture Certificate Program! The counts of the downy mildew sporangia from a field are always a few days behind due to processing of the spore tapes. Although it can be a problem in field, hoop house and greenhouse conditions, there have not been any reports of it in Minnesota. View the spore trap results and current downy mildew news. A spore trap placed in Muskegon County detected downy mildew sporangia for one day last week but diseased plants have not yet been confirmed in this county. Commercial growers should read and follow all application instructions in the Midwest Vegetable Production Guide. In wet or very humid conditions, disease develops rapidly. Issued in furtherance of MSU Extension work, acts of May 8 and June 30, 1914, in cooperation with the U.S. Department of Agriculture. If found in a home garden, remove and destroy diseased plants immediately to prevent spreading to other plants. To have a digest of information delivered straight to your email inbox, visit https://extension.msu.edu/newsletters. Both contact and systemic fungicides are available for use against downy mildew. Downy Mildew, caused by Pseudoperonospora cubensis, is an oomycete that is not a true fungus. This is one of the most common and destructive diseases affecting all cucurbit crops in the eastern United States including New York. Downy mildew … Jeffrey W. Dwyer, Director, MSU Extension, East Lansing, MI 48824. Systemics are more effective if weather conditions are conducive to disease and the host is very vulnerable. The disease outbreak consisted of several plants with the characteristic “window-pane” yellow-brown lesion bordered on each side by the leaf veins (Photos 1-2). Cucumber varieties with moderate to high level of resistance are available. Cucurbit downy mildew is a major disease that affects all cucurbits. This early infection is possibly due to a change in the pathogen's biology or due to greenhouse production of cucurbits that allows the pathogen to overwinter on living plants. Growers in other regions of the state could consider a 10-day application schedule until the first outbreak is detected. Check out the MSU Agricultural Industries Certificate Program! It thrives in wet or very humid conditions as a water mold. Reference to commercial products or trade names does not imply endorsement by MSU Extension or bias against those not mentioned. Delaying fungicides until downy mildew is already well-established in the field is not recommended because it can be too late to protect the crop and this delay contributes to the downy mildew pathogen developing resistance to our most important, effective fungicides. Under humid conditions, downy mildew rapidly reproduces and spreads, resulting in severe crop damage. It is very important that cucumber growers use a proven downy mildew program with fungicides that have shown good activity in our yearly Michigan research plots including: *Note: Previcur Flex is back in the downy mildew fungicide recommendations for 2020 as it has been effective in the MSU research trials in 2018 and 2019. It thrives in wet or very humid conditions as a water mold. Some resistant varieties are available for pumpkins and winter squash, but this is usually specific to certain pathotypes of downy mildew and may not be effective in all cases. Connect with Commercial Fruit and Vegetable, Downy mildew of cucumber, melon and squash. The disease affects cucurbit crops in the field and those grown in passive or traditional greenhouses.