![]() ![]() Under dry conditions, little sporulation will be present and leaves may appear scorched (M.Fruit typically develop greasy, gray-brown lesions that expand rapidly and may cause fruit cracking.Sporulation is more common on the underside of plant leaves. ![]() ![]() Under humid or rainy conditions, late blight lesions on stems, leaves, and fruit will develop white-gray sporulation.A number of other fungicides have efficacy for late blight (see ID-36, pages 79 and 104) for best results, these should be applied preventatively. Outdoor Insecticide and Mite Killer for Organic Gardening: Eight Insect Control Vegetable, Fruit and Flower, 32 oz. Multi-Purpose Fungicide, Insecticide and Miticid: Captain Jacks Deadbug Brew Ready-to-Use Spray, 32 oz. Sprays with a protectant fungicide (such as chlorothalonil, mancozeb, or copper) are the minimum recommendation for both tomato and potato crops in eastern Kentucky prior to the next rain event. Reading the claim that this would work on tomato blight led me to the false hopes it would.It is often too late to save the crop if fungicide sprays are delayed until symptom development. After researching treatments for early and late blight, I found great data on the Cornell Universitys Ag department web page. Late blight can destroy a field in a matter of weeks during wet, cool weather.If you garden organically, adding compost extracts or teas can be a treatment. US-23 genotypes can infect both tomato and potato and have varying sensitivity to Ridomil (according to Steven Rideout at Virginia Polytechnic Institute). A fungicide intended for different plants, not vegetables, won’t make a difference and may cause problems. This pathogen recently found in Maryland was genotyped as US-23, the most commonly found genotype in recent years.Many of the systemic fungicides typically used for early blight and Septoria (such as Fontelis, Cabrio, or Topsin) will not be effective against the late blight pathogen. Aside from these chemicals, mancozeb and maneb can also be used in home applications. It can be applied the day before you pick tomatoes, and the fact that it is effective until then indicates its low toxicity. The pathogen is Phytophthora infestans, which is a water mold. We recommend chloratlonil as a chemical treatment for tomato fungus.Like other water mold-induced diseases, such as blue mold and cucurbit downy mildew, late blight spreads rapidly within and between fields, and quickly becomes a grower community problem. Initially, a brown to black lesion usually develops on the stem near the soil line. Symptoms and Signs On tomato and pepper, the most common symptom occurs on the lower stem where it is in contact with the soil. If late blight is suspected, the local county Extension agent should be contacted as soon as possible. Pathogen Southern blight is caused by the soil-born fungus Athelia rolfsii ( Sclerotium rolfsii ). While unlikely, the possibility exists that with a swirling, southwesterly weather pattern, spores from infected plants there could affect tomato and potato crops in eastern KY, particularly if those spores are deposited under wet conditions. Last week, late blight was found on greenhouse tomato transplants in the westernmost county in Maryland, which is approximately 250 miles from the eastern border of Kentucky. ![]()
0 Comments
Leave a Reply. |