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…
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Abstract. Lygus bugs are a severe pest of bean production in many parts of the Central Valley. Insecticides should be combined with other management approaches to provide cost-effective management of this pest. Registered and experimental insecticides were evaluated to determine their efficacy against lygus bugs (adults and nymphs) and impacts on bean yield and quality in blackeye cowpeas…
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The objective of this project is to evaluate new products for management of root-knot nematode on carrots. Root-knot nematodes (Jvfeloidogyne sp.) are widely distributed throughout California and are the most important nematode pest of carrot. CwTent control methodology relies on the use of Metam sodium and Telone II.
The potential for loss of the standard chemical nematicides due to various environmental concerns is great enough to warrant…
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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)…
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Greenhouse studies have evaluated the impact of metam sodium applications, with and without solarization films and associated soil heating, on development of FOV symptoms in varieties of cotton previously recognized as highly-susceptible (a Pima, Phytogen 810-R or DP-744) or moderately susceptible (an Acala, Phytogen-72). The soil media used was a 1:2 mix of soil from a highly infested field site mixed with steam-treated potting mix. Trays of soil mix received the treatments and post-treatment, the soil was transferred into clean, waxed cardboard containers to plant out the seed for further evaluations of disease symptom development and plant survival percentages. In metam sodium trials, three different rates of metam sodium alone did not significantly impact the survival rate (about 30%) or symptoms (root vascular stain index rating averaging about 3 on a scale of 0 (no symptoms) to 5 (severe symptoms) in highlysusceptible Pima varieties. In the moderately susceptible Acala variety, the metam sodium treatments improved the survival rate and reduced vascular stain ratings wl1en compared with untreated soil. In the first trial, averages of about 90% survival were recorded for treated soil versus about 60% survival for untreated. In the second trial, an average of about 90% survival was recorded for treated soil versus…
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PROJECT SUMMARY
In California, Fusarium wilt of cotton has been considered a potentially serious fungal disease caused by the organism Fusarium oxysporum vas infectum (also called “FOV”). However, in the past, damage associated with Fusarium in SJV cotton has been notable only in production areas with the combination of: (a) moderate to high populations of a specific race of FOV (usually race 1 ); (b) soils witl1 a sandy or sandy loam texture; and (c) root knot nematodes present in high-enough populations to cause significant galling and root damage. Past research generally indicated that FOV damage was worst when both FOV inoculum and nematodes were present in relatively higl1 concentrations. Methods used in the past to limit damage to cotton associated with Fusarium wilt have been to avoid planting cotton in soils in which the combination of sandy or sandy loam texture is combined with the presence of root knot nematode, or grow cotton only infrequently…
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Abstract. The late-season sucking in sect complex (cotton aphids and sweetpotato whiteflies) has hindered cotton production in the San Joaquin Valley (SJV) during the 2000’s. The effects on cotton quality have been most problematic. Insecticides are a primary management tool for late-season insect infestations and Lorsban® 4E is a commonly used treatment. Recent concerns over volatile organic compounds in the SJV have pinpointed emulsifiable concentrate pesticide formulation s, particularly Lorsban 4E, as contributing factors. The activity and mode of action of this formulation make it ideal for controlling aphids on the leaf undersides within the large canopy. This research examined the efficacy of alternative chlorpyrifos formulations and other aphid-active materials against mid-season and late-season infestations of cotton aphids and as a second objective pinpointed and refined the threshold level for treatment of populations. Members of the neonicotinoid class of chemistry, organophosphates, and carbamates and single representatives from the pyridinecarboxamide and pyridine azomethines classes were compared. Aphid populations in 2007 were fairly low and well below threshold values. For mid-season populations, 12 of the 19 treatments provided at least 80% control. Assail® 70WP and Carbine® exhibited the best combination of speed-of-kill, efficacy, and residual control. Aphid control during the late-season…
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Changes in the California cotton industry enacted in 1998 allow for a much broader range of varieties to be grown in the SJV. It will be important for growers to have unbiased sources of varietal performance information that will answer some of the questions regarding yield performance, growth characteristics and quality of available varieties. These trials involving newly-available CA Upland varieties complement the combined SJV Cotton Board and the UCCE Farm Advisor Approved Acala studies. Trials include standard varieties of Acalas in order to have some more complete indices of varietal comparisons. The range of yield potential as well as the range of quality characteristics across the varieties now available will mean that growers have an even more difficult job than usual in balancing the combination of yield and quality (and resulting price)…
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The objectives of these studies with Pima cotton are primarily to evaluate new, approved, and high interest varieties under different environmental conditions and management regimes practiced at REC sites and grower fields across the San Joaquin Valley region of California. Variety evaluations for yield and quality performance for varieties submitted into these trials are initially the responsibility of the San Joaquin Valley Cotton Board. The farm advisors extend these evaluations by adding some continuing field testing of newly-approved and high interest varieties to the Pima tests of the SJV Cotton Board. Pima acreages continue to change. The reason for continuing changes in acreages is overall reductions in planted cotton acreage in California in recent years, but part is also related to increasing shifts to Pima. There are tradeoffs in shifting to Pima (typically reductions in yields) and in shifts to non-Acala Uplands (typically lower price for lint), and growers need reliable, unbiased information regarding expected lint yields and fiber quality in order to make reasonable, lower-risk decisions. Acreage will continue to be volatile with changing input costs and disparities in cotton prices between non-Acala Upland, Acala and Pima cottons…
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Acala cotton varieties were grown on about 100,000 acres out of the greatly reduced total acreage of about 275,000 acres in 2008. Part of the reason for continuing changes in acreages is overall reductions in planted cotton acreage in California in recent years, but part is also related to shifts to Pima and non-Acala Upland cotton. There are tradeoffs in shifting to Pima (typically reductions in yields) and in shifts to non-Acala Uplands (typically lower price for lint), and growers need reliable, unbiased information regarding expected lint yields and fiber quality in order to make reasonable, lower-risk decisions. The San Joaquin Valley Cotton Board will remain the avenue for varieties to enter our “Approved Variety” testing program. Within Acala testing, the combined SJV Cotton Board and the UCCE Farm Advisor Approved Acala trials represents a source for broadly-based information on varietal performance. Separate trials involving newly-available CA Upland varieties continue to be conducted by Hutmacher and staff at Shafter and West Side REC sites to complement SJVCB I Approved Acala studies. Variety evaluations for yield and quality performance for…
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