![]() ![]() The fruit and foliage remain susceptible.īacterial leaf spot resistance is complicated by the pathogen having multiple races. Resistance to phytophthora root rot is only in the root and crown phases. Don’t produce transplants from treated and nontreated seeds in the same greenhouse.Ĭhoose resistant varieties but know the issues. Always pre-test seed before treating a large seed lot. “When you decide to treat seed, treat all of the seeds going into a seed lot,” Miller said. The Ohio State University Extension Factsheet Hot Water and Chlorine Treatment of Vegetable Seeds to Eradicate Bacterial Plant Pathogens is an excellent guide on seed treatment and is available at. “Seed treatment with bleach is quite simple,” Miller said. ![]() Treating seeds with hot water or dilute bleach is important and works best with raw seed. “But remember, ‘pathogen-tested’ does not guarantee ‘pathogen-free’.” Many pepper diseases – especially those caused by bacterials – are seedborne and the message continues to be only use clean seed. Managing pepper diseases requires an integrated management program. and has led to numerous USDA import restrictions (see Vegetable Growers News, January 2020 issue, page 18). TBRFV is a very serious disease that is not present in the U.S. “It was only recognized a couple of years ago and has turned the tomato and pepper industries into an uproar,” Miller said. Tomato brown rugose fruit virus (TBRFV) is new and also mechanically-transmitted. Mechanically-transmitted viruses include the tobamoviruses which include tobacco mosaic virus (TMV) and tomato mosaic virus (ToMV). Cucumber mosaic virus (CMV) is another insect-transmitted virus and is spread by aphids. These viruses include tomato spotted wilt virus (TSWV) and impatiens necrotic spot virus (INSV). Insect-transmitted viruses include the tosporviruses which are most typically transmitted by thrips. ![]() Virus diseases that affect peppers fall into two categories – insect-transmitted and mechanically-transmitted. “It looks like bacterial leaf spot,” Miller said, and is often misidentified. Syringae leaf spot has emerged as a new, seedborne, bacterial disease. It infects plants through wounds and is associated with insect damage of the fruit. Bacterial canker’s classic symptom on peppers is rough, raised spots on the underside of leaves.īacterial soft rot is favored by warm, wet weather. It affects peppers but doesn’t kill them and can be mistaken for other diseases. “Moisture is the driver for all of the pepper diseases.”īacterial canker is a devastating, seedborne disease of tomatoes, but is less common in peppers. “The key through all of this is moisture,” Miller said. It’s triggered by hot, moist conditions but is short-lived in the soil in cool climates. It’s seedborne and can overcome disease resistance. It’s a long-lived pathogen – both in the soil and in water.īacterial leaf spot is the most common and most important bacterial disease of peppers. It’s favored by warm, rainy conditions and can be spread by contaminated surface water. Phytophthora often starts in low spots or other areas of poor drainage. The result is moisture stress and stunted, unproductive plants. “I see the most of this when you plant peppers into cool, moist soil and then it gets hot,” Miller said. ![]() Pythium root rot is favored by saturated soils, kills the roots and may even spread up into the crown. It has many hosts, produces many spores and is ubiquitous to pepper production. Grey mold (botrytis) is favored by cool, moist, humid conditions. White mold is favored by cool, wet, humid conditions and can be more of a problem in hoop houses where there is less air movement and higher humidities. The anthracnose lesions on the peppers are full of spores that are moved around by rain or irrigation. “It’s extremely aggressive,” Miller said. It’s favored by warm, wet weather and the damage mainly appears on the fruit. “Peppers get fewer diseases than tomatoes but in general they get hammered harder,” said Sally Miller, professor in vegetable pathology at Ohio State University and a speaker at the recent Great Lakes Fruit, Vegetable & Farm Market EXPO in Grand Rapids, Michigan.Īnthracnose was a non-issue in peppers a decade ago but has emerged as a major concern. Peppers face fewer plant pathogens than other crops but diseases are still a big concern. ![]()
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