![]() ![]() Issued in furtherance of MSU Extension work, acts of May 8 and June 30, 1914, in cooperation with the U.S. 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. 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. Hausbeck's work is funded in part by MSU's AgBioResearch. This material is based upon work supported by Cooperative Agreement 58-6 with USDA ARS under the Floriculture and Nursery Research Initiative, and the IR-4 Project.ĭr. T is for Thielaviopsis root rot on ornamentalsĪcknowledgments.R is for Rhizoctonia rot on ornamentals.P is for Pythium root rot on ornamentals.P is for Phytophthora rot on ornamentals. ![]() ![]() Learn more about the ABCs of ornamental greenhouse diseases Aerial stem blight and sporulation on vinca. Botrytis sporulation on a blighted geranium leaf. *Not recommended when disease pressure is high. Botrytis A Team (ornamental recommendations only)īotrytis B Team * (ornamental recommendations only) Note that although there are differences in sporulating leaves (percent) for the two intervals of each product (as shown by the bar heights), that difference is not statistically significant (as shown by letters in common on the bars).Įvaluation of minimum and maximum labeled application intervals of ornamental fungicides for control of Botrytis blight on geranium. The graph is a comparison of minimum and maximum application intervals of fungicides applied to geranium to control Botrytis. B Team products are a good rotational choice when disease pressure is not severe. Newer ornamental products, Pageant and Palladium, make excellent rotational choices in a spray program. The graph below shows that even the best treatments do not completely prevent infection however, they are often necessary partners in a successful management program that includes environmental control and sanitation. When treating ornamentals for Botrytis blight, rotate among products with different FRAC codes to reduce the possibility of resistance developing in the Botrytis fungus.įungicides listed in the A Team table consistently provide effective control. The FRAC code is an alphanumeric code assigned by the Fungicide Resistance Action Committee and is based on the mode of action of the active ingredient. The “A” and “B” Team tables of recommended ornamental Botrytis fungicides are the result of multiple trials conducted at Michigan State University. If you have dead plant tissue on your greenhouse bench, it is likely supporting sporulating Botrytis!įungicides must be applied to ornamentals as a foliar spray to be effective in controlling Botrytis blight. Sanitation is an important first step to reduce Botrytis in your greenhouse. Reduce the relative humidity for a minimum of 24 hours immediately following the harvesting of cuttings to help “dry” the wounded stems and thereby limit stem blight.įinding the beginnings of brown/gray fuzziness on lower leaves can signal the need for disease control measures. Reducing relative humidity by spacing plants further apart and providing good air circulation can be helpful. Watering in the morning so the foliage can dry rapidly is one way to minimize Botrytis. Water allows the Botrytis conidia to germinate and penetrate the plant. Plants may also be susceptible if they become wet from water dripping from overhead, dew or condensation. When the weather is moist and humid, susceptible plants may need to be protected from Botrytis infection. Botrytis can also infect dead plant tissue in the pot or on the greenhouse bench or floor, which can be a source of future infections. On bedding and stock plants, Botrytis typically becomes established and produces conidia on older lower leaves that are near the moist soil surface and under the plant canopy. Infection that can start as a small leaf spot that can quickly coalesce into a large necrotic area or infect the cut stem surface of stock plants and progress downward, causing a dieback of the entire plant. Botrytis produces large masses of gray conidia or spores (hence the name “gray mold”) that can be carried on air currents to healthy plants where blight can become established. Botrytis causes leaf spots (Photo 1), blighting ( Photos 2-5), stem cankers and damping-off. Botrytis cinerea is a fungus that infects many greenhouse ornamental and vegetable crops. ![]()
0 Comments
Leave a Reply. |