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, upper panel; trial 2, lower panel) for inoculated (gray bars) and mock-inoculated (open bars) CM334 or NuMex Heritage 6-4 (NMH6-4) plants challenged with Phytophthora capsici strains, PWB24 or PWB 54. * indicates significant difference based on

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). Thus, chili pepper is a high-value crop, contributing to economic benefits for producers ( Barchenger et al. 2018 ). Sweet and hot peppers present variable degrees of susceptibility to soilborne pathogens such as Phytophthora capsici , Verticillium

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Phytophthora blight, caused by Phytophthora capsici, is a widespread problem of many vegetables including bell peppers. Four bell pepper cultivars marketed as resistant/tolerant to P. capsici include `Paladin' (resistant), `Alliance' (tolerant), `Aristotle X3R' (tolerant), and `Revolution' (tolerant). These cultivars, along with four other widely grown cultivars (`Commandant', `King Arthur', `Legionnaire', and `Red Knight X3R') and a susceptible control (`California Wonder'), were evaluated for their performance in a commercial field highly infested with P. capsici. `Paladin' had the lowest incidence of Phytophthora blight and the greatest yield compared to all other cultivars. `Alliance', `Aristotle X3R', and `Revolution' (the tolerant cultivars) also had lower Phytophthora blight incidence and greater yields compared to the other five cultivars evaluated. Results indicated that in fields that historically have high incidence of Phytophthora blight, `Paladin' could be a reliable choice for commercial production.

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Management strategies for Phytophthora blight (caused by Phytophthora capsici) in bell pepper production are limited and there is no single method that will consistently provide adequate control. Twelve bell pepper cultivars (including four marketed as resistant/tolerant to P. capsici) were transplanted into a P. capsici-infested field and were managed with or without fungicide applications. The fungicide applications consisted of: i) Mefenoxam (Ridomil Gold EC, 1.2 L/ha) at transplant; and ii) a spray application of Dimethomorph (Acrobat, 0.45 kg/ha) + Copper (Tenn-Cop, 3.6 L/ha) alternated with Manganese ethylenebisdithiocarbamate (Maneb, 2.8 kg/ha) + Copper (Tenn-Cop; 3.6 L/ha) at 10- to 14-day intervals. Regardless of cultivar, the standard fungicide program reduced the incidence of Phytophthora blight and resulted in greater yields and farm-gate revenues when compared to the no fungicide program. Across all cultivars, total farm-gate revenues per hectare were $6,773 and $3,674 for the standard fungicide program and the no fungicide program, respectively. For P. capsici-tolerant cultivars, farm-gate revenues improved with the use of the standard fungicide program by $1,316, $4,427, and $5,447 per hectare for `Aristotle X3R', `Revolution', and `Alliance', respectively, compared to no fungicide applications. Furthermore, farm-gate revenue for P. capsici-resistant `Paladin' was improved by $3,240 per hectare when a standard fungicide program was used. Results indicate that although plant resistance is an important component of a P. capsici bell pepper management program, the use of recommended fungicides could improve disease control and increase farm-gate revenues.

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Phytophthora capsici is a serious soilborne pathogen in chile pepper [Capsicum annuum L.] in New Mexico, and has been shown to spread under high soil moisture conditions and cause losses in a wide array of crops worldwide. This study was conducted to assess whether soil water saturation predisposes chile pepper to infection by P. capsici. Potted chile pepper plants of `Criollo de Morelos 334' (`CM334') and `New Mexico 6-4' (`NM6-4'), resistant and susceptible to P. capsici, respectively, were subjected to soil water saturation conditions (saturated and nonsaturated) for 3 and 6 days at two growth stages (six- to eight-leaf stage and one- to four-flower bud stage) prior to being inoculated or noninoculated with zoospores of P. capsici. Regardless of growth stage, no disease symptoms developed in `CM334' grown either under saturated or nonsaturated soil conditions at any of the two periods (3 or 6 days) of soil water saturation. In `NM6-4', disease symptoms consisting of stem necrosis, defoliation, and wilting were expressed. Plant growth stage at inoculation had a significant effect on disease severity (P < 0.0001). However, the response of `NM6-4' to P. capsici at each growth stage under saturated soil conditions was similar to that under nonsaturated conditions regardless of the period of saturation (P = 0.09). These results indicate that soil water saturation does not exert a significant predispositional effect on infection of chile pepper by P. capsici.

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The oomycetous pathogen, Phytophthora capsici Leonian, is capable of causing several disease syndromes in cucurbits, including crown rot, foliar blight, and fruit rot ( Roberts et al., 2001 ; Zitter et al., 1996 ). Crown rot appears at the soil

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Three Korean cultivars, Pungkak, Kalmi, and Subi, were crossed with PI 201234, which has resistance to P. capsici. A backcross breeding program was initiated to incorporate the Phytophthora resistance into the Korean cultivars, but the level of resistance decreased as the backcross round increased. Highly resistant plants occurred frequently in the BC1F2 populations but were rare in the BC2F1 populations. Resistant plants selected in BC1F3 populations had nearly enough recovery of the growth and fruit characteristics of the Korean recurrent parents. Crosses were made between resistant selections in each BC1F2 population. The F1 hybrids showed a considerably increased level of resistance.

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Cucumber ( Cucumis sativus ) production in the eastern and midwestern United States is subject to severe losses due to fruit rot caused by the soilborne oomycete pathogen, Phytophthora capsici ( Granke et al., 2012 ; Sonogo and Ji, 2012 ). P

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Fruit rot induced by Phytophthora capsici Leonian is an increasingly serious disease affecting pickling cucumber (Cucumis sativus L.) production in many parts of the United States. The absence of genetically resistant cultivars and rapid development of fungicide resistance makes it imperative to develop integrated disease management strategies. Cucumber fruit which come in direct contact with the soil-borne pathogen are usually located under the canopy where moist and warm conditions favor disease development. We sought to examine whether variations in plant architecture traits that influence canopy structure or fruit contact with the soil could make conditions less favorable for disease development. As an extreme test for whether an altered canopy could facilitate P. capsici control, we tested the effect of increased row spacing and trellis culture on disease occurrence in the pickling cucumber `Vlaspik'. Temperature under the canopy was lowest in trellis plots, intermediate in increased spacing plots, and highest in control plots. Disease occurrence in the trellis plots was significantly lower than in other treatments, indicating that preventing fruit contact with the soil reduced disease occurrence. The effect of currently available variation in plant architecture was tested using nearly-isogenic genotypes varying for indeterminate (De), determinate (de), standard leaf (LL), and little leaf (ll) traits. Plants with standard architecture had higher peak mid-day temperatures under the canopy and greater levels of P. capsici infection; however, levels of disease occurrence were high for all genotypes. Screening a collection of ≈150 diverse cucumber accessions identified to serve as a representative sample of the germplasm, revealed variation for an array of architectural traits including main stem length, internode length, leaf length and width, and number of branches; values for `Vlaspik' were in the middle of the distribution. Plant architectures that may allow for more open canopies, including reduced branching habit and compact growth, were tested for disease incidence. One of the compact lines (PI 308916), which had a tendency to hold young fruit off the ground, exhibited lower disease occurrence. The reduced disease occurrence was not due to genetic resistance, suggesting that architecture which allows less contact of fruit with the soil could be useful for P. capsici control for pickling cucumber.

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, caused by the oomycete pathogen Phytophthora capsici , is a severe disease affecting squash and pumpkin. Originally described in 1922 after being identified on pepper [ Capsicum annum ( Leonian, 1922 )], it was first reported on cucurbits (Cucurbitaceae

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