Botrytis

Botrytis blight commonly also known as gray mold is a fungal infection that affects a wide array of plants both ornamental and edible. Most known for its attack on grapes, tomatoes and strawberries, botrytis can cause extensive losses to crops as it directly affects the fruit of the plant as well as the crowns, stems, flowers and any other part of the plant aside from the roots. Gray mold is so named by the characteristic grey mold appearance of its spores. Botrytis favors cooler conditions in the spring and is often observed after several days of wet drizzly weather followed by slightly warmer humid weather which can spread the existing disease. The fungus overwinters in dead plant debris and makes its appearance in the spring when the weather warms up a bit. The spores that are produced are easily blown off of the plant to germinate and infect more plants a process that can take only a few hours. Once the fruit of plants is affected by botrytis it must be discarded as it is inedible, this can have a significant impact on commercial crops particularly in areas that are rainy, cool and humid in the spring. There are a number of good agricultural practices that can help prevent and control botrytis and in areas that are susceptible to this type of fungal disease it is very important to practice these techniques before an infection begins. Control of botrytis begins with cleaning up all dead plant debris as this is where botrytis overwinters.

Be sure to either burn or dispose of the debris that has been already infected with botrytis. When planting plants that are vulnerable to botrytis, be sure to give them plenty of room in between plants and plant in a place that provides good air circulation. Keep the area well weeded and remove any debris that might inhibit air circulation around the plants. Carefully inspect plants for botrytis frequently, removing any dead plant parts, and anything that looks as though it may have disease on it. If the entire plant is infected at the base you may wish to consider removing the entire plant as it is better to lose one plant than the entire crop. Be sure to do your inspections when the plants are dry, as handling them when wet can cause the spores to spread and germinate more rapidly.

Be sure to always water plants from below and avoid spraying leaves and fruit since botrytis needs moisture to grow, the drier you can keep the plants the better chance you will have of controlling any potential disease outbreak. Fungicides can be an effective way to prevent botrytis; there are several effective fungicides that work very well against this disease. You will want to spray in the spring if it has been cool and damp or if you have a history of botrytis infections. Read the instructions on the label of the fungicide for how much and often to apply it as all fungicides vary. If you are looking for a highly effective fungicide that is less toxic on the environment than conventional fungicides then take a look at the products from Marrone Bio Innovations. They are committed to producing products that have the least amount of impact on the environment while still being as effective as possible.