Cotton, Gossypium hirsutum L., cultivars and breeding lines were evaluated in the field for resistance to the Cotton Leaf Crumple disease caused by Cotton Leaf Crumple Virus (CLCrV, Genus Begomovirus, Family Geminiviridae) transmitted by silverleaf whitefly, Bemisia argentifolii (Bellows and Perring). Cultivars and breeding lines were evaluated in field plots during 1999 through 2001 in the Imperial Valley, CA. Cotton entries were rated for severity of CLCrV disease symptoms, and the titer of CLCrV in leaves of selected plants of each cultivar/breeding-line was determined by dot blot hybridization with a CLCrV DNA probe and/or PCR analysis. DNA sequencing of geminivirus DNA-A and DNA-B fragments, PCR-amplified from symptomatic cotton plants, confirmed geminivirus infection and allowed for partial characterization of CLCrV in the Imperial Valley. Differences in whitefly infestation levels and virus disease severity were detected among cotton entries. The breeding lines NK 2387C and DPX 1883 had the lowest CLCrV disease severity ratings and viral titers, suggesting a high level of virus resistance. Lines DG 2165 and DG 2383 had few or no CLCrV symptoms and low viral titers, and are moderately resistant. Stoneville 474 and NK 2207 had visible CLCrV symptoms and higher virus titers, and cultivars AP 4103 and AP 6101 had the highest CLCrV disease ratings and high levels of CLCrV; these cultivars/lines are susceptible. These results indicate that there are promising sources of resistance available for CLCrV disease in the United States; it will be important to ascertain whether these sources are resistant to the devastating cotton leaf curl disease in Asia, which is caused by a different

Sweetpotato whitefly (SWF): Bemisia tabaci (Gennadius) -biotype BThe objective of the study was to evaluate the efficacy of insecticides for control of SWF on broccoli under low desert growing conditions.Broccoli ('Marathon') sets were transplanted on 20 Sep 2016 at the University of California Desert Research and Extension Center, El Centro, CA into double row beds on 40 inch centers, with a spacing 5 inch between plants.Stand establishment was achieved using overhead sprinkler irrigation and thereafter furrow irrigation was used for plant health maintenance.Plots were four beds, 13.3 ft wide by 50 ft long and bordered by one untreated bed.Four replications of each treatment were arranged in a RCB design.Insecticidal compounds, formulations, application methods, application rates, and application date are provided in Table 1.All soil insecticide treatments were applied on 16 Sep concentrated into a 1-inch band and applied 3-inch below the soil surface in the transplant-lines using shank injection delivering 28.3 gpa, under 80 psi.All foliar spray insecticide treatments were applied with a Lee Spider Spray Trac Tractor, four-row sprayer with three TJ-60 11003VS nozzles per row delivering a directed spray application at 50 psi and 63 gpa on 4 and 18 Oct, 2016.An adjuvant, Dyne-Amic surfactant (Helena

Cucurbit yellow stunting disorder virus (CYSDV) reduces melon (Cucumis melo L.) fruit quality and yield in many parts of the world. Host plant resistance of melon to CYSDV is a high priority for sustainable melon production in affected production areas. High-level resistance to CYSDV exhibited by TGR 1551 (PI 482420) appeared, initially, to be controlled by a dominant gene, based on greenhouse tests in Malaga, Spain that were terminated 28 to 42 days post-inoculation (DPI). We report here results of tests that were evaluated over periods ranging from 49 DPI (Malaga) to 91 DPI (Texas) following exposure to CYSDV that show resistance to CYSDV in TGR 1551 to be a recessive trait. Mean CYSDV symptom severity rating of F-1 TGR 1551 x 'Dulce' did not significantly differ from the mean rating for TGR 1551, but the F-2 distribution suggested a recessive gene for resistance to CYSDV in controlled inoculation, greenhouse tests in Texas. The F-1 TGR 1551 x 'Bola de Oro' was susceptible in a greenhouse in Malaga, where it exhibited CYSDV symptoms and was positive for CYSDV infection prior to symptom expression. TGR 1551 clearly expressed recessive genetic resistance in open field tests in Imperial Valley, California where the mean symptom severity ratings of 'Top Mark' and the F-1 TGR 1551 x 'Top Mark' were not significantly different, and the F-2 and respective testcrosses confirmed recessive resistance to CYSDV.

Beet armyworm (BAW), Spodoptera exigua (Hu ¨bner) Cabbage looper (CL), Trichoplusia ni (Hu ¨bner)The objective of the study was to evaluate the efficacy of various insecticide treatments against worm pests (BAW and CL) on cabbage under desert growing conditions.Cabbage ('Gazelle') was direct seeded on 20 Sep 2016 at the University of California Desert Research and Extension Center, Holtville, CA into double row beds on 40 inch centers.Stand establishment was achieved using overhead sprinkler irrigation, and furrow irrigation was used thereafter.Plots were four beds (13.3 ft) wide by 50 ft long and bordered by one untreated bed.Four replications of each treatment were arranged in a RCB design.Insecticidal compounds, formulations, and application rates are provided in the table.All insecticide treatments were foliar sprays applied on the dates specified in Table 1 with a Lee Spider Spray Trac Tractor, four-row sprayer with three TJ-60 11003VS nozzles per row that delivered 63 gpa at 50 psi.An adjuvant, Syl-Tac (Wilbur-Ellis Company LLC, FRESNO, CA 93755) was added at 0.25 vol/vol% to each foliar spray mixture.A pre-treatment (PT) sampling of BAW and CL from 25 plants per replicate, was completed on 28 Sep 2016, 6-days prior to treatment applications.Due to the sparse population of BAW and the more abundant population of CL, Loopex was added to the treatment list after 12 Oct treatments.Starting on Oct 19, all treatments tank mixtures were buffered to pH 7.0.Starting on Oct 19, CL and BAW were counted as small larvae (first to early third instar) and large (late third to fifth instar).Data results for small BAW (128 total or 93.75%) and large BAW (8 total or 6.25%) are not shown due to the very small numbers; only pooled data results of small and large BAW are shown.BAW post treatment samples were taken 2-days after treatment the first (2-DAT1), 7-DAT1, 2-DAT2, 7-DAT2, 2-DAT3, 6-DAT3, 9-DAT3, 13-DAT3, 2-DAT4, 7-DAT4, 12-DAT4, and 15-DAT4; on 6 Oct, 11 Oct, 14 Oct, 19 Oct, 21 Oct, 25 Oct, 28 Oct, 1 Nov, 4 Nov, 9 Nov, 14 Nov, and 17 Nov 2016.CL posttreatment samples were taken 7-DAT2, 2-DAT3, 6-DAT3, 9-DAT3, 13-DAT3, 2-DAT4, 7-DAT4, 12-DAT4, and 15-DAT4; on 19 Oct, * This research was

The objective of the study was to evaluate the efficacy of insecticides used against worm pests (larvae of BAW, AC, and AWW) on alfalfa grown for hay production under desert growing conditions. An insecticide efficacy trial was conducted at the UC Desert Research and Extension Center, Holtville, CA, on a stand of CUF-101 alfalfa. The experimental design was RCB using four replicates with five insecticide treatments and an untreated check. Plots were 30-ft wide by 50-ft long. Formulations and rates for each compound are provided, and test materials were applied on 29 Jul 2016 at the specified rate equivalencies listed in the tables. Each broadcast spray application was made as a single 30-ft wide swath, through 17 nozzles (TJ6

Cucurbit yellow stunting disorder virus (CYSDV), emerged in the Sonoran Desert region of the southwestern USA in 2006 and has become well established. Symptoms induced by CYSDV infection include a striking interveinal chlorosis or yellowing and reduced yield and quality. The virus is transmitted by Bemisia tabaci, and the cryptic species MEAM1 has been present in the region since the early 1990s. CYSDV has now become the most economically important of the viruses affecting cucurbit production in the southwestern US. Here, we present a review of recent studies on CYSDV in the southwestern US, with implications for management of this virus throughout the world. Field surveys have established that CYSDV results in late-season infection of spring melon crops with limited economic impact; however, all summer and fall cucurbits become infected shortly after emergence due to high B. tabaci populations and abundant sources of inoculum. Studies have also demonstrated that CYSDV has an extensive host range among crops and weeds prevalent in the region. Recent studies demonstrated considerable variation in virus accumulation and transmission rates among the host plants evaluated as potential reservoirs. Cucurbit hosts had the highest CYSDV titers, were efficient sources for virus acquisition, and showed a positive correlation between titer in source plants and transmission to cucurbit plants. Non-cucurbit hosts had significantly lower CYSDV titers and varied in their capacity to serve as sources for transmission. Experiments demonstrated that multiple factors influence the efficiency with which a host plant species will be a reservoir for vector transmission of CYSDV to crops. Melon PI 313970 was identified as a new source of host plant resistance to CYSDV, in addition to the previously identified TGR 1551 (=PI 482420) and TGR 1937 (=PI 482431). Potential new sources of CYSDV resistance were identified by field screening of ca. 500 melon accessions with naturally occurring inoculum from 2007 through 2012. Host plant resistance to B. tabaci has also been identified in melon germplasm resistant to CYSDV and could be an important factor in reducing losses to CYSDV. Resistance to CYSDV is being transferred to US western shipping type cantaloupe and honeydew.

Sweetpotato whitefly biotype B (MEAM1 cryptic species of Bemisia tabaci; SPWF) feeding severely impacts fall season melon (Cucumis melo L.) yield and quality in the lower deserts of California and Arizona. Melon accessions PI 313970 and TGR 1551 (PI 482420) have been reported to exhibit host plant resistance (HPR) to SPWF. Potentially higher and lower levels of HPR to SPWF were observed in ad hoc comparisons of numbers of adults per leaf on six melon accessions, PI 313970, TGR 1551, 'Impac', and 'Top Mark' in a naturally infested field test at Holtville, CA in fall 2012. Replicated field tests at Holtville in fall 2013 and spring 2014 (when SPWF populations are lower than in the fall) compared SPWF infestation of five (PI 116482, PI 123689, PI 124107, PI 124431, PI 145594) of the six accessions with PI 313970, TGR 1551, TGR 1937 (PI 482431), 'Top Mark' and 'Impac'. Statistically significant differences were found in both seasons among the entries for numbers of adults per sampled leaf, eggs, crawlers, red eyes, or nymphs cm(-2) leaf area at many but not all sampling dates. Though there were significant (P<0.05) differences among the entries for number of adults per sampled leaf at seven weekly sampling dates in fall 2013, none of the accessions had consistently fewer adults than 'Impac' or 'Top Mark'. There were few differences among the entries in spring 2014 for numbers of adults per sampled leaf. PI 116482 had the most, and PI 145594, PI 313970 and TGR 1937 had the fewest adults, on average.

spotted alfalfa aphid | Therioaphis trifolii

The objective of the study was to evaluate the efficacy of various new and standard insecticides against sweetpotato whitefly (SWF) on upland cotton under desert growing conditions.Cotton was direct seeded on 13 Apr 2015 at the University of California Desert Research and Extension Center, Holtville, CA, into single row beds on 40-inch centers.Stand establishment was achieved with furrow irrigation; used thereafter.Plots were two beds wide by 50-ft long and bordered by one nontreated bed.Five replications of each treatment were arranged in an RCB design.Insecticide names, formulations, and rates of treatment for each compound are provided in the tables.The applications were made on 26 Jun and 10 Jul 2015 with a Lee Spider Spray Trac operated at 30 psi delivering 16.9 gpa.A broadcast application was delivered through 4 TJ-60 11003VS nozzles covering four beds.The adjuvant, Hasten Modified Vegetable Oil (Wilbur-Ellis Company, Fresno, CA) at 16 fl oz per acre was added to each spray mixture for all foliar spray treatments.Populations of whitefly adults, eggs, and nymphs were evaluated on 24 Jun, 2 day pretreatment (2-PT); 7 Jul, pretreatment (PT) sample taken just prior to spray applications; 29 Jun, 3-d after treatment 1 (3-DAT1); 2 Jul, 6-DAT1; 10 Jul, 14-DAT1; 13 Jul, 3-DAT2; 17 Jul, 7-DAT2; 24 Jul, 14-DAT2.Adult populations were estimated by taking leaf turn samples and recording direct counts on the undersides of leaves.Leaves selected for adult counts were fifth main stem node leaves below the plant terminus from five randomly selected plants per plot and reported as adults per leaf.Immature (eggs and nymphs) densities were estimated by extracting a single fifth main stem node leaf from five randomly selected plants per plot.Extracted leaves were bagged, labeled, and taken into the laboratory where densities of eggs and nymphs were counted on the abaxial surface of a 2 cm 2 leaf disks from the lower, left-hand quadrant of each sample leaf using a binocular dissecting microscope.Immature densities were tallied from the five 2-cm 2 leaf disks on each sample date and reported as eggs or nymphs per 10 cm 2 .Harvest data of seed cotton per 0.001 acres were collected on 30 Sep 2015 (one row

The objective of the study was to evaluate the efficacy of foliar insecticide spray applications for control of aphids on leaf lettuce under desert growing conditions. Leaf lettuce, “Bergram’s Green” was direct seeded on 4 Nov 2014 at the University of California Desert Research and Extension Center, Holtville, CA into double row beds on 40 inch centers. Stand establishment was achieved using overhead sprinkler irrigation, and irrigated via furrow irrigation thereafter. Plots were four 40 inch beds (13.3 ft) wide by 40 ft long with one non-planted bed between plots and 5 ft between blocks. Five replications of each treatment were arranged in a RCB …

The objective of the study was to evaluate the efficacy of insecticides for control of onion thrips and western flower thrips on dehydrator onions under desert growing conditions. Dehydrator onion (White Creole) was direct seeded into six row beds on 40 inch centers on 25 Oct 2013 at the University of California Desert Research and Extension Center, El Centro, CA. Stand establishment was achieved using overhead sprinkler irrigation initiated on 28 Oct 2013; Sprinklers were used until January 2014 and furrow irrigation was utilized thereafter. Plots were four beds 13.3 ft wide by 50 ft long and bordered by two-buffer beds between plots and 3 ft beffers between replicate blocks. The experiment included 11 insecticidal treatments and an untreated check. Four replications of each treatment were arranged in a RCB design. Insecticidal compounds, formulations and application rates, along with treatment dates, are provided in Table 1. All insecticide treatments were foliar sprays applied with a Lee Spider Spray TracTractor 4-row sprayer …

Arthropod Management Tests ( AMT ) may be ESA's least understood journal. It publishes original research, but not in the standard format of research manuscripts submitted to the other ESA scientific journals. AMT is editor-reviewed rather than peer-reviewed and has its own style guide format, emphasizing brevity; it was formerly a print publication but is now online-only. With the support of ESA's partners at Oxford University Press, we have had the opportunity to make significant upgrades on behalf of AMT ’s authors and readers. If you aren't familiar with AMT , …

The objective of the study was to evaluate the efficacy of various insecticide treatments against worm pests (DBM and CL) on cabbage under desert growing conditions. Cabbage, ‘Red Jewel’ was direct transplanted on 14 Oct 2015 at the University of California Desert Research and Extension Center, Holtville, CA into a row on beds of 40 inch centers. Stand establishment was achieved using overhead sprinkler irrigation, and furrow irrigation was used thereafter. Plots were four beds (13.3 ft) wide by 50 ft long and bordered by one untreated bed. Four replications of each treatment were arranged in a RCB design. Insecticidal compounds, …

The objective of the study was to evaluate new insecticides for their efficacy against adults and nymphs of WTPB and other insect pests on alfalfa grown for seed production under desert conditions. An insecticide efficacy trial was conducted at the UC Desert Research and Extension Center, Holtville, CA on a stand of CUF-101 alfalfa on beds of 40-inch centers; the stand was sprayed with Dibrom 8 @ 1.5 pt/acre on 20 May 2013 to control pests prior to initiating seed production. The experimental design was RCB using four replicates with 11 insecticide treatments and an untreated check. Plots were eight beds 40 ft wide by 70 ft long, with 5 ft buffers between replicate blocks. The insecticide treatments were applied on the dates at the specified rate equivalencies listed in Table 1. The insecticide treatments were broadcast sprays applied with a Lee Spider Spray Trac, tractor mounted spray boom, equipped with 15 nozzles (TJ-60 11003VS), operated at 30 psi and delivering 36 gpa in a 20-ft wide spray swath. Hasten, a modified vegetable oil surfactant (Wilber-Ellis Company), was applied at 0.25% vol/vol in tank mixtures with each insecticide treatment. The pretreatment (PT) insect population …