INTEGRATION OF BIOLOGICAL AND CHEMICAL CONTROLS FOR RHIZOCTONIA AERIAL BLIGHT AND ROOT-ROT OF ROSEMARY

Aerial blight, caused by Rhizoctonia solani AG-4, was identified as a major disease of greenhouse mist-produced rosemary cuttings. An isolat e of the biocontrol fungus Laetisaria arvalis, selected for tolerance to the experimental fungicide CGA 173506, was used as an amendment to potting soil. Combined treatment of rosemary with L. arvalis and a fol iar spray of the fungicide at one-half the recommended rate reduced di sease more than treatment with either the fungus or fungicide alone. S imilar synergism was not observed for combinations of Trichoderma harz ianum as a soil amendment and a foliar spray of the fungicide iprodion e applied at the labeled rate.