Archives

University of CA and USDA-ARS Fusarium Screen Summary – 2013 trials

 

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

Download full copy of Research here

Management of Root-knot Nematode

 

This project has the following two objectives:
1. Evaluate new products for management of root-knot nematode on carrots.
2. Evaluate the effectiveness of trap crops for management of root-knot nematode on carrots.

Root-knot nematodes (Meloidogyne sp.) are widely distributed throughout California and are the most important nematode pest of carrot. Current control methodology relies on the use ofMetam sodium and Telone II.

The potential for loss of the standard chemical nematicides due to various environmentally…

 

Download full copy of Research here

UCCE Approved Acala and Pima Variety Trials

 

The objectives of these studies with Acala and Pima varieties are to evaluate approved Acala varieties and Pima varieties submitted for testing under different environmental conditions and management across the San Joaquin Valley region of California. In order to provide a reasonable limit on the number of varieties in the tests, the entries include newly-approved varieties (approved by the San Joaquin Valley Cotton Board) for the current year, varieties released last year that are in their second year of testing, plus the top 4 or 5 previously-approved varieties (in terms of planted acreage). The new varieties are the focus of tests, but only remain in tests for a minimum of two years following release unless that variety moves into the top 4 or 5 varieties in planted acreage. Released varieties also may not show up in tests if companies request that the variety is for a special market and don’t want it in multiple location testing, or when seed supplies are inadequate. The Pima tests focus on approved varieties, but in the past two years have also included a non-approved hybrid that has been of interest due to yield…

 

Download full copy of Research here

Sticky Cotton Prevention – Late Season Insect and Defoliation Management

 

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

Development of Sampling and Decision Plans for Silverleaf Whitefly on Pima

 

INTRODUCTION

Bemisia whitefly populations are a significant annual threat to cotton production, particularly pima cotton, in the San Joaquin Valley. This pest has the potential to reduce cotton yields; however, the prospect of cotton lint contamination, creating a condition called sticky cotton, is the primary concern associated with whitefly infestations. Important research on sampling, damage potential, and management of Bemisia whiteflies has been conducted in Arizona. This research has formed the backbone of our present management scheme in California. In summary, this research supported three stages of whitefly management during the season with different insecticide chemistries during each stage. The need to management resistance and the characteristics…

Download full copy of Research here

INTERACTION OF COTTON NITROGEN FERTILITY PRACTICES AND COTTON APHID POPULATION DYNAMICS IN CALIFORNIA COTTON

 

Introduction:
During the last 10 years, the cotton aphid (Aphis gossypii) has developed from a non-pest to one of the most significant insect pests of California cotton. For instance,in1997, cotton aphid outbreaks were severe and an estimated 3.5% yield loss occurred despite -$40/acre control costs which were incurred. Cotton aphid infestations during the mid-season (July to mid-August) reduce cotton lint yields since the aphids act as a significant sink, competing with the bolls, for energy. The late-season infestations (mid-Aug.to Sept.) are problematic because the aphids deposit honeydew on the exposed cotton lint, which reduces the lint value. Reasons for this change in pest status of cotton aphid are unclear; however, one of the most noticeable changes in cotton production over the last 10 years is the use of a plant growth regulator instead of irrigation and nitrogen deficits to limit early-season cotton vegetative growth. This has allowed cotton production practices in the SJV to evolve to higher nitrogen fertilization and irrigation inputs.

 

Download full copy of Research here