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cucurbit downy mildew. Symptoms of cucumber downy mildew appear mostly on the foliage. Infection first appears as small, water-soaked lesions on the underside of leaves. Initially, lesions may be round in shape, becoming angular, because they are bound by

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Cucurbit leaf crumple geminivirus (CuLCrV) is transmitted by sweet-potato whitefly (Bemisia tabaci) biotype B (SPWF-B) and occurs on cucurbits in Arizona, California, Texas, and Mexico. This virus is identical to Cucurbit leaf curl virus, and their symptoms are similar to Squash leaf curl virus on squash (Cucurbita sp.) and Melonleaf curl virus on melon (Cucumis melo L.). Melon has been reported to be either susceptible to CuLCrV, or to have the ability to recover from infection. Twenty-three melon cultigens were inoculated with CuLCrV in greenhouse tests using SPWF-B. Eighteen of the cultigens tested were highly susceptible to CuLCrV (≥60% infected plants) and generally exhibited pronounced CuLCrV symptoms: `Amarillo', `Edisto 47', `Esteem', `Fuyu 3', `Impac', `Moscatel Grande', `Negro', `Perlita', PI 234607, PI 236355, PI 414723, `PMR 5', `Seminole', `Sol Dorado', `Sol Real', `Top Mark', `Vedrantais', and WMR 29. Five cultigens were resistant to CuLCrV (<40% infected plants that exhibited restricted, mild symptoms): MR-1, PI 124111, PI 124112, PI 179901, and PI 313970. Symptoms abated with time in both groups although infected plants remained positive for the virus. Ten of the cultigens (`Edisto 47', `Fuyu 3', `Impac', MR-1, PI 124112, PI 313970, PI 414723, `PMR 5', `Top Mark', and WMR 29) were included in field tests in 2003 and 2004 that were naturally infected with CuLCrV. With the exception of PI 414723, the greenhouse and field data were consistent for reaction to CuLCrV.

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Clomazone was evaluated for reemergence weed control in summer squash, watermelon, cantaloupe, cucumber, and pumpkin. Clomazone was applied preplant incorporated or surface-applied after planting. All crops exhibited varying degrees of chlorosis in the cotyledonary stage and first one to three true leaves. Cucurbit tolerance to clomazone was pumpkin = squash > cucumber > watermelon > cantaloupe. Method of application did not affect crop vigor. Some pumpkin cultivars were more tolerant than others. Clomazone controlled Brachiaria platyphylla and Portulaca oleracea with both methods of application. Surface application provided better control of Amaranthus hybridus and A. spinosa. Mollugo verticillata was not controlled. Preplant incorporated application of clomazone tended to reduce the yield of watermelon.

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Plant problems often are diagnosed by comparing the problem in hand to a set of color photographs of known symptoms. Color photographs are expensive and time consuming to publish and distribution of books and pamphlets is costly. Delivery of high resolution color photographs of common plant disorders via the World Wide Web is a cost-effective alternative. A web-based diagnostic resource has been created to assist problem identification of cucurbit disorders including nutritional, disease, and insect problems. The diagnostic tool consists of arrays of high resolution, color images grouped by similarity of appearance. The image arrays are clickable image maps, and the user is provided with increasingly detailed information and larger images as images are selected. At the final selection, the user is presented with a full screen image and text information describing the identity and control recommendations for the problem illustrated. This tool is intended to allow experienced diagnosticians to confirm a problem diagnosis, and to aid less experienced individuals in making proper diagnoses.

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Cucurbit powdery mildew (CPM), a major problem of melon ( Cucumis melo L.) production worldwide, is mostly caused by two fungi: Podosphaera xanthii and Golovinomyces cichoracearum (DC) V.P. Heluta (formerly Erysiphe cichoracearum ) ( Jahn et

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indicated a potential benefit for watermelon production. An up-to-date list of cucurbit rootstock options for growers is available online ( Kleinhenz, 2015 ). Table 1. Comprehensive list of rootstock, scion, and pollinizer cultivars used in replicated field

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Alabama, where the growing seasons of cucurbit vegetables [e.g., yellow squash and zucchini ( Cucurbita pepo ), cucumber ( Cucumis sativus )] and agronomic crops [e.g., cotton ( Gossypium hirsutum )] overlap during the year, allowing for the insect to

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‘Inodorus’ melon HortScience 42 521 525 Davis, A.R. Perkins-Veazie, P. 2005 Rootstock effects on plant vigor and watermelon fruit quality Cucurbit Genet. Coop. Rpt. 28 39 42 Fernández, G

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Cucurbit downy mildew is one of the most devastating and widespread diseases of cultivated cucurbits in the United States and worldwide ( Call et al., 2013 ; Lebeda et al., 2011 ; Ma and Cui, 1995 ; Neykov and Dobrev, 1982 ; Thomas, 1996 ). The

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Prevention of the introduction of bacterial fruit blotch of watermelon, caused by Acidovorax avenae subsp. citrulli, into the transplant house or field is the most effective control strategy. Watermelon seedlots currently are screened for A. avenae subsp. citrulli, but other cucurbits, often grown in the same transplant house or field, generally are not as carefully monitored. In 1997 and 1999 field tests, cultivars of watermelon, muskmelon, honeydew melons, acorn squash, butternut squash, yellow squash, zucchini squash, cucumber, and pumpkin were evaluated for foliar and fruit susceptibility to bacterial fruit blotch and for seed transmission of A. avenae subsp. citrulli. The bacterium was introduced into the field on infected watermelon transplants or by misting a bacterial suspension onto fruit of the cucurbits. Foliar and fruit symptoms were more extensive in the watermelon, muskmelon, and honeydew melons than in the other cucurbits. In greenhouse grow-out assays, seed transmission of A. avenae subsp. citrulli was detected in every cucurbit in at least one of the two seasons, even though there were no fruit symptoms in some of them. Thus, any cucurbit crop plant should be considered a potential source for the introduction of A. avenae subsp. citrulli into the transplant house or field.

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