47 research outputs found
A seed midge pest of big bluestem
A Cecidomyiid midge reared from the panicles of big bluestem (Andropogon gerardii Vitman (var. gerardii) at Mead, Neb., was identified as Contrarinia wattsi Gagne. This midge was previously known only from panicles of little bluestem (Schizachyrium scoparium (Michx.) Nash) in New Mexico. In Nebraska, C. wattsi appears to have a minimum of 3 generations per season. Larvae of the earlier generations leave the florets after completing development, making it difficult to associate floret damage with the midge. Larvae of the last generation of a season remain in diapause, in the floret, throughout the winter. Evidence obtained in this study in 1985 indicates that, at harvest time, 7 and 15% of the florets in the 2 fields studied contained diapausing midges. However, when an estimate of seed loss by the earlier generations (as indicated by empty florets and small seed) was considered, the total loss was probably closer to 40%. An unidentified species of thrips (Thysanoptera: Thripidae) also was found in big bluestem florets during this study. However, evidence suggests that thrips do not damage big bluestem seed as seriously as the midge
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Control of Ctirus Thrips by Avermectin
Two rates of Avermectin were mound- applied; one treatment of Avermectin B one of Carzol were applied by air to citrus in April for control of citrus thrips. Plots were sampled by beating new terminal growth and counting thrips. Ground applications had fewer thrips than applications made by air. Avermectin B1 treatments had significantly fewer thrips than Carzol at all sample dates
A seed midge pest of big bluestem
A Cecidomyiid midge reared from the panicles of big bluestem (Andropogon gerardii Vitman (var. gerardii) at Mead, Neb., was identified as Contrarinia wattsi Gagne. This midge was previously known only from panicles of little bluestem (Schizachyrium scoparium (Michx.) Nash) in New Mexico. In Nebraska, C. wattsi appears to have a minimum of 3 generations per season. Larvae of the earlier generations leave the florets after completing development, making it difficult to associate floret damage with the midge. Larvae of the last generation of a season remain in diapause, in the floret, throughout the winter. Evidence obtained in this study in 1985 indicates that, at harvest time, 7 and 15% of the florets in the 2 fields studied contained diapausing midges. However, when an estimate of seed loss by the earlier generations (as indicated by empty florets and small seed) was considered, the total loss was probably closer to 40%. An unidentified species of thrips (Thysanoptera: Thripidae) also was found in big bluestem florets during this study. However, evidence suggests that thrips do not damage big bluestem seed as seriously as the midge
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Update on Fuller's Rose Beetle in Arizona
Initial studies of Fuller rose beetle (FRB) biology have found some adult emergence in late June and early July. No adults woe found in foliage in May or early June, nor was activity noted in August and early September. FRB were not found in early October, but they began expected major emergence in mid-October. Several FRB collected did not have fused wings, atypical for this species. This finding suggests flight ability in FRB, currently unknown to occur
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Effect of Fungicides on Development of Cercospora Summer Black Stem and Leaf Spot in Alfalfa
Cercospora summer black stem and leaf spot, a fungal disease of alfalfa, has been associated with a stand decline problem in La Paz County. In a continuation of a study initiated in 1987, we examined the ability of three fungicides to control the disease and decline problem. Bravo, Funginex, and Kocide significantly reduced the severity of Cercospora summer black stem and leaf spot. In addition, significant increases in yield were recorded on plots treated with fungicides
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The Role of Cercospora Summer Black Stem and Leaf Spot in the Alfalfa Decline Problem in La Paz County
An alfalfa decline problem has appeared recently in fields between Poston and Parker in La Paz County. Cercospora summer black stem and leaf spot, a fungal disease of alfalfa, has been associated with the decline problem. The efficacy of three fungicides were tested for control of the disease and the decline problem. Bravo, Kocide, and Spotless significantly reduced the severity of Cercospora summer black stem and leaf spot; however, significant increases in yield were not realized. Alfalfa decline in La Paz County may involve other factors in addition to plant disease
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Effects of AuxiGro® WP and Fertilizers on Upland Cotton in the Palo Verde Valley, 2002
A field experiment was conducted to obtain data from upland cotton grown under low desert conditions to document of the effects of AuxiGro® WP and treatments consisting of AuxiGro® WP plus various foliar fertilizers on cotton yield and quality. Treatments were applied the morning of July 6, 2002, to DPL 655BR cotton that had begun bloom approximately June 28. Yields and quality data were obtained and economics calculated. AuxiGro by itself did not result in a yield increase, but did so in combination with various fertilizers. Highest quality resulted in the 8 oz/acre rate of AuxiGro + Foliar Pride fertilizer, but highest yields were documented from the 4 oz./acre rate of AuxiGro + CalMax. All treatments increased harvested value of cotton/acre when compared with the untreated check, with the treatment consisting of 4 oz./acre rate of AuxiGro + CalMax worth almost $200/acre more than the untreated check
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Effect of Sunstainable Versus Conventional Fertilization Practices on Populations of Pythium and Fusarium on Roots of Lettuce in 1990 Field Test
This report focuses upon our efforts to evaluate the effect of sustainable versus conventional fertilization practices on subsequent populations of soil-borne pathogens on lettuce roots. The different fertilization treatments included conventional fertilizer, composted cow manure, and a biological soil conditioner. Near plant maturity, lettuce roots were collected from the field and the populations of Pythium and Fusarium were determined. The lowest population of both of these pathogens was found in the plots fertilized with composted cow manure, while the highest levels of Pythium and Fusarium were detected in the plots treated with conventional fertilizer. Further field studies are planned to confirm these initial findings. Of the two pathogens assayed, Pythium is of greatest concern because of its ability to destroy roots and reduce plant growth and vigor. Species of Fusarium are commonly found in soil and on plant roots and usually do not cause damage to plants unless the plants are under stress