Investigation of Spray Application of Microbial Herbicides Using Alternaria alternata on Amaranthus retroflexus

Author： Lawrie J. Greaves M. P. Down V. M. Western N. M. Jaques S. J.

ISSN： 1360-0478

Source： Biocontrol Science and Technology, Vol.12, Iss.4, 2002-08, pp. : 469-479

Disclaimer: Any content in publications that violate the sovereignty, the constitution or regulations of the PRC is not accepted or approved by CNPIEC.

Previous Menu Next

Abstract

Inclusion of Alternaria alternata conidia in a spray formulation affected the distribution pattern on the target. The dry weight of Amaranthus retroflexus plants was reduced by more than 83% when A. alternata conidia (107 ml^-1) were applied at 200 L ha^-1 or greater and when given a 24 h dew period. At low application volumes (25 or 50 L ha^-1) plant dry weight was reduced by only 29 or 54%. After 7–8 h dew period, conidial germination on the leaf surface was 11–19%. This increased to 62–91% after 24 h dew period. Counts of conidia on leaves indicated that up to 86% of the conidia sprayed were not retained on the target plant, or did not reach it. This is reflected in lesion numbers per unit area being only 3–5% of the calculated theoretical numbers. The results cast doubt on the suitability of A. alternata as a microbial herbicide for the control of Am. retroflexus.