conidia can grow and survive for days before penetration, unlike most spores that need to penetrate within hours to ensure survival. Once infection occurs, the conidia are produced in these lower leaf regions. Assuming favorable weather conditions (see below), these conidia serve as secondary inoculum for upper leaf regions, as well as husks and sheaths (where it can also overwinter and produce conidia the following season). Additionally, wind and heavy rains tend to disperse the conidia during many secondary cycles to other parts of the field causing more secondary cycles of infection. If conditions are unfavorable for inoculation, the pathogen undergoes a state of dormancy during the winter season and reactivates when humid conditions favorable to inoculation return the following season. The fungus overwinters as stromata (mixture of plant tissues and fungal mycelium) in leaf debris, which give rise to conidia causing primary inoculations the following spring and summer. Environment Corn grey leaf spot is found by Crous et al. 2006 to flourish under extended periods of high relative humidity (over two days) and free moisture on leaves due to fog, dew, or light rain. Additionally, heavy rains tend to assist in dispersal of the pathogen. Temperatures between are also required. If the temperature drops below during wet periods or lacks 12 hours of wetness, the extent of disease will be greatly diminished. In the Midwest and Mid-Atlantic, these conditions are favorable for spore development during the spring and summer months. The infection cycle may take two to four weeks depending on the environment and susceptibility of the corn product used. Management In order to best prevent and manage corn grey leaf spot, the overall approach is to reduce the rate of disease growth and expansion. This is done by limiting the amount of secondary disease cycles and protecting leaf area from damage until after corn grain formation. High risks for corn grey leaf spot are divided into eight factors, which require specific management strategies. factors for grey leaf spot in corn: Susceptible hybrid Continuous corn Late planting date Minimum tillage systems Field history of severe disease Early disease activity (before tasseling) Irrigation Favorable weather forecast for disease There are currently five different management strategies, some of which are more effective than others. Resistant varieties The most proficient and economical method to reduce yield losses from corn grey leaf spot is by introducing resistant plant varieties. In places where leaf