Aguyoh JN., Gaoquiong L. , Ochieng J.
Abstract
A research to investigate the influence of greenhouse cover material on insect pest infestation, powdery mildew and
rose petal blackening was carried out in three commercial rose farms in Kenya. The farms are situated in Kericho,
Eldoret and Juja. The research was carried in two phases: Field survey with most information being collected through
structured questionnaire and on site tests. Rose petal blackening was not associated with any type of green house
cover, but was dependent on the age of the cover material. The highest number (15.7mites/plant) of mites was observed
at the Juja flower farm, an area associated with high temperatures. Powdery mildew infection was significantly high in
the three year old polyethylene covered greenhouses compared to the level of infestation in the greenhouses with new
covers. The spectral transmission properties of greenhouse covering materials tested indicated that the amount of solar
energy transmitted to the plant canopy is influenced by the position at which the radiation is taken. As the covering
material ages, the percent petal blackening of roses as well as powdery mildew increases thus affecting the quality of
flowers.
Key words:
Rose petal blackening, spectral transmission, greenhouse temperature, aphids, mites, powdery mildew