Fusarium w.ilt of cotton in California has been considered a potentially serious fungal disease caused by the organism Fusarium oxysporum vas infectum (also called ”FOV”) for many decades in several areas of the San Joaquin Valley (SJV). In the past, however, damage associated with FOV in SJV cotton has been notable only in areas with the combination of: (a) moderate to high populations of one or more specific races of FOV (usually race 1 ); (b) soils with a sandy or sandy loam texture; and (c) where root lrnot nematodes were present in high-enough populations to cause some significant root damage. Past research generally indicated that FOV damage was worst when both FOV inoculum and nematodes were present in relatively high…
Download full copy of Research here
Preventing sticky cotton is crucial in producing quality cotton. Late-season populations of cotton aphid and Silverleaf whitefly can produce significant amounts of honeydew when populations build. These pests are of most concern from mid-boll filling through harvest, when insect populations build and threaten exposed lint. Pest management guidelines for cotton aphid and silverleaf whitefly focus on strategies to use once threshold pest populations are reached, with the approach varying with the composition of the developing population (nymphs, adults), crop growth stage, and with the presence of exposed lint. Current pest management guidelines for whitefly and aphid can be interpreted as meaning defoliation is the final event of the season. This is based on the assumption…
Download full copy of Research here
Justification and Problem Statement
The Western tarnished plant bug, Lygus hesperus is a major pest of cotton in the San Joaquin Valley and a closely related species, L. lineolaris, is quickly becoming the primary pest of cotton in the Southeast US. Research in the past few years aimed at developing a control strategy that targets the pest species and sustains natural enemy populations, which would otherwise be killed by chemical pesticides that are currently used. Beauveria bassiana is a fungal pathogen that infects a wide range of insect hosts including Lygus bugs. Commercial formulations of this fungus are…
Download full copy of Research here
Justification and Problem Statement
Lygus hesperus continues to be one of the most damaging pests of cotton in the San Joaquin Valley. L. lineolaris, a
closely related species is quickly becoming the primary pest of cotton in the Southeast US. Current controls consist
ofthe application of broad spectrum pesticides that may also impact natural enemies. The depletion of natural
enemies may lead to increases of other pests such as aphids, whiteflies and spider mites later in the season. A
control that is selective for Lygus would be a benefit to the cotton industry. Both Lygus species are infected, in
nature, by a fungus called Beauveria bassiana. B. bassiana occurs worldwide, and is used commercially. Tests in
our laboratory and in published reports suggest that the commercial products are not very effective against either
Lygus species (Noma and Stickler 2000; Steinkraus and Tugwell 1997). Surveys for B. bassiana done in 2000-2002
revealed widespread prevalence of the fungus (McGuire 2002). B. bassiana was found in all SJV…
Download full copy of Research here