Submitted to: Weed Science Society of America Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 2/3/1997
Publication Date: N/A
Technical Abstract: Application cost and timings of delivery to target weed are major considerations in the development of mycoherbicides. An effective delivery system in which the biocontrol agents are applied at planting is desirable. In controlled environment experiments, soybean and rice seed were inoculated with mycoherbicidal fungal propagules (spores or microsclerotia) )of: Colletotrichum truncatum (COLTRU), [host: hemp sesbania (Sesbania exaltata Rydb. ex A.W. Hill)]; C. gloeosporioides f. sp. aeschynomene (CGA) [host: northern jointvetch (Aeschynomene virginica (L.) B.S.P.)]; or Alternaria cassiae (AC), [host: sicklepod (Cassia obtusifolia L.)]. Various substances were tested for their ability to adhere the mycoherbicides to crop seed coats. The most effective adherents were dilute sodium aglinate and dilute wall paper paste (containing methylan cellulose). Crop seed were treated by one of two methods. In the first method, seed were sprayed dwith or immersed in adherents containing fungal spores. In the second method, seed were sprayed with or immersed in adherents and subsequently shaken in dry spore preparations (AC); a dry spore commercial formulation (CGA); or microsclerotia formulated in diatomaceous earth (COLTRU). In a separate test, crop seed were inoculated with a combination of each dried fungal formulation. The treated seed were air dried, and stored at 4 C or 20 C. The treated seed were planted in potting soil containing weed seed. Infection and kill of weeds was directly related to distances from crop seed to weed densities. Seed germination and crop growth were unaffected by any of the mycoherbicides. After six months storage under either temperature, COLTRU (microsclerotia), CGA (dry commercial formulation) and AC provided excellent control of all weed species.