Phytotoxicity of benomyl to crucifers was influenced by cultivar, seedling age, chemical concentration, and the presence or absence of a surfactant.  Seedlings of cabbage cultivar Eastern Ballhead, and cauliflower cultivars Clou and Idol were highly sensitive to benomyl (0.154 mg/g oven dry soil); whereas seedlings of cabbage cultivars Red Rock, Early Greenball, King Cole, and Chieftain Savoy, broccoli cultivars Spartan Early and Green Comet, and brussels sprouts cultivars Jade Cross and Catskill were tolerant.  Seedlings of cabbage cultivar Eastern Ballhead were severely stunted when seeds were sown in benomyl-treated soil, but were only slightly affected when seedlings were treated at 8 weeks of age.  Plant growth was not affected by benomyl at rates below 0.154 mg/g soil; cabbage, cauliflower, and brussels sprouts were stunted at rates above this concentration.  When surfactants GAFAC RA-600 or GAFAC RS-710 (mixtures of mono- and diphosphate esters) (1:99, v/v) was added to benomyl or applied to filter paper and soil, seed germination and seedling emergence of cabbage cultivar Eastern Ballhead were less than when the filter paper and soil were treated with benomyl alone.  This effect was not observed when 1% of the surfactant Tween 20 (polyoxyethylene sorbitan monolaurate) was added to benomyl.

Additional key words: Benlate, systemic fungicide.