OBJECTIVES OF RESEARCH:
2013 was the second year and 2014 is the third year of a field research trial that focuses on deficit drip management practices that could be utilized to tighten up and shorten the fruit production period and evaluation of these practices using both full-season commercial Acala and Pima cultivars and experimental germplasm (USDA-ARS and/or commercial companies)…
University of CA and USDA-ARS Fusarium Screen Summary – 2013 trials
Hutmacher, Wright, Ulloa et al – February 2014
Univ. California and USDA-ARS Fusarium-Race 4 Screenings (THREE SITES: Kern County and Tulare County sites plus greenhouse site at Kearney REC – 2013)
2013_Fusarium Race 4 Field Ratings SUMMARY TABLE – means and std deviations only
Justification and Problem Statement
The western tarnished plant bug is a key pest of cotton in western arid production regions. Populations of lygus bugs are difficult to monitor because adults are active fliers, and nymphs inhabit cryptic habitats and move rapidly when disturbed. Management decisions are complicated by these difficulties. Because the principal management tactic for lygus bugs is chemical pesticides, treatment decisions based on inaccurate sampling data may result in either unnecessary crop loss, or unneeded pesticide applications that my contaminate the environment and induce secondary pests. Considerable effort has been devoted in cotton production regions of the West and Mid-South to evaluate and improve sampling methodology for lygus bugs. However, in recent efforts the criteria for the selection of sampling methods have focused on maximum numbers of bugs collected or apparent precision of population estimates without consideration for the fidelity of those estimates to actual bug populations. Development of efficient and practical absolute or near-absolute sampling methods for one or more stage of lygus would allow more meaningful evaluation and perhaps calibration…
Objectives: To improve cotton germplasm with potential heat stress tolerance, better fiber quality, lint yield and pest resistance, broadening the genetic base of cotton.
Justification and Problem Statement
Over the last 3 5 years, the cotton germplasm base used in plant breeding has narrowed. This relatively narrow genetic diversity has been suggested as a contributor to an apparent plateau in breeding progress. It may also represent an impediment to efforts to sustain high yields (May and Taylor, 1998; Meredith, 1992; Ulloa, 2006). Since the re-establishment of a cotton breeding effort within the USDA-ARS, Western Integrated Cropping Systems Research Unit, we have focused on increasing genetic diversity through acquisition of novel germplasm (from multiple sources including non-commercial land races and species of wild cottons)…
Justification and Problem Statement
The western tarnished plant bug is a key pest of cotton in western arid production regions Populations of lygus bugs are difficult to monitor because adults are active fliers, and nymphs inhabit cryptic habitats and move rapidly when disturbed. Management decisions are complicated by these difficulties. Because the principal management tactic for lygus bugs is chemical pesticides, treatment decisions based on inaccurate sampling data may result in either unnecessary crop loss, or unneeded pesticide applications that my contaminate the environment and induce secondary pests. Considerable effort has been devoted in cotton production regions of the West and Mid-South to evaluate and improve sampling methodology for lygus bugs. However, in recent efforts the criteria for the selection of sampling methods have focused on maximum numbers of bugs collected or apparent…
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…
Summary:
Cotton is routinely grown in the hot, irrigated areas of the far Western U.S., and these extended periods of high temperature can reduce cotton ( Gossypium hirsutum L. and G. barbadense) lint yield, even with adequate irrigation conditions. Extended periods of extremely high temperatures are common in these areas during the critical stage of peak flowering. When temperatures in the San Joaquin Valley reach temperatures above normal during the critical stage of peak flowering, California growers suffer the consequences of reduced yield by these cotton varieties weaknesses to heat. The number of cotton commercial varieties for California with heat tolerance is not really known. However, it is known that Acala varieties Maxxa and Phytogen 72 yield poorly in the heat stress environment of…
Summary:
Since the re-establishment of the USDA-ARS, WICS, genetic/breeding program, we have been focusing on bringing germplasm from any possible source available to us in order to increase genetic diversity. Most of the time, the genetic diversity in the cotton crop is used as an indicator to recognize potential threats to sustaining high yields. In the last couple of years, several troubling developments have recognized Fusarium oxysporum f.sp. vasirifectum (FOV) Atk. Sny & Hans as a recurring and potentially expanding threat to cotton production. The vulnerability of cotton production to this pathogen highlights the need for comprehensive research to protect the cotton industry from FOV, both from virulent populations which may be introduced and new virulent strains arising from within cotton production areas. Until recently, only race 1 and race 2 were known to occur in the United States (DeVay, 1986; Smith et al., 1981). UC scientists have recently identified race 4 ofFOV in cotton plants…
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…
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…
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