EFFECTS OF SIMULATED AND NATURAL SUNLIGHT ON THE GERMINATION OF CONIDIA OF METARHIZIUM FLAVOVIRIDE GAMS AND ROZSYPAL AND INTERACTIONS WITH TEMPERATURE

The effects of natural and simulated sunlight on conidia of Metarhiziu m flavoviride Gams and Rozsypal formulated in oil were investigated. T he germination responses of conidia exposed to simulated sunlight usua lly followed an exponential pattern, but a cubic relationship was bett er in one instance when the conidia were allowed a longer time to germ inate. Conidia exposed to natural sunlight in West Africa showed cubic relationships in their germination responses and greater inactivation /increment of ultraviolet (UV) dose compared with that from simulated sunlight. This was probably due to the greater intensity of UV irradia tion compared with simulated sunlight, but and interaction with temper ature occurs naturally in the field. Under laboratory and field condit ions, UV light caused increasing levels of damage as the temperature r ose; with simulated sunlight, UV levels that caused a 20% reduction in germination at 20 degrees C caused an 80% reduction at 50 degrees C.