SYMPOSIA PAPER Published: 01 January 1989

An Invert Emulsion Replaces Dew in Biocontrol of Sicklepod — a Preliminary Study


Applications of the fungus, Alternaria cassiae Jurair and Khan with and without an overspray of a new experimental invert (water-in-oil) emulsion were evaluated for control of sicklepod (Cassia obtusifolia L.) weed in soybeans ‘Forrest’ with and without a post-treatment dew period under controlled environmental conditions. The unique experimental invert emulsion was developed and applied with specialized air-assist atomizing nozzles as an overspray to provide moisture and to retard evaporation of the water applied so that the fungal spores could germinate and infect the target weeds under relatively dry conditions. Spores applied in an aqueous carrier alone or in an aqueous carrier followed by an overspray of the invert emulsion caused 100 percent mortality by 16 days after treatment if the sicklepod seedlings were exposed after treatment to 18 h of dew. Spores applied in the aqueous carrier alone and in the aqueous carrier followed by an overspray of the invert emulsion caused 0 and 88 percent mortality, respectively, without the dew period. This is the first report known to us of a technique to obtain infection and weed control with a foliar-applied weed pathogen without dew or mist.

Author Information

Quimby, PC
Fulgham, FE
Boyette, CD
Connick, WJ
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Developed by Committee: E35
Pages: 264–270
DOI: 10.1520/STP26463S
ISBN-EB: 978-0-8031-5106-2
ISBN-13: 978-0-8031-0979-7