Effects of Border Crops and Intercrops on Control of Cucurbit Virus Diseases

Abstract

In five field trials over 3 years, control of aphid-transmitted, nonpersistent virus diseases on pumpkin, caused mostly by the potyviruses Watermelon mosaic virus (WMV) and Papaya ringspot virus type-W (PRSV-W), was achieved by intercropping with grain sorghum, as opposed to clean tillage. Reductions in disease incidence ranged from 43 to 96% (P ≤ 0.05). Surrounding pumpkin plots with borders of peanut, soybean, or corn was not effective. Borders of grain sorghum were effective, but disease control was generally less than for the intercrop treatment. Intercropping soybean and peanut with pumpkin reduced disease incidence by 27 to 60% (P ≤ 0.05), but disease control generally was less than for grain sorghum. Peak periods of alate aphid immigration generally preceded virus disease outbreaks by 7 to 14 days. However, alate landing rates, as measured in green tile traps, did not differ among treatments. Marketable yield was not increased by the intercrop treatments, and yield was reduced by up to 50% for the intercrop treatment with grain sorghum in two trials. The use of grass-selective herbicide applied along pumpkin rows, reduced seeding rates of the intercrops, or mowing did not alleviate the adverse effects of competition between pumpkin and the grain sorghum intercrop on yield.

Effects of Irrigation Methods and Water Regimes on Occurrences of Cucumo- And Poty- Viruses in Watermelon

“…This could be attributed to the fact that watermelon belongs to the family cucurbitacea, hence, its susceptibility to cucurbit viruses. The susceptibility of cucurbits to CMV and Potyviruses have been reported by many authors (Choi et al, 2000;Damicone et al, 2007;Lecoq, 2003).…”

Cultural Practices Influencing Biological Management of Crop Diseases

“…Borders of grain sorghum were effective, but disease control was generally less than for the intercrop treatment. Intercropping soybean and peanut with pumpkin reduced disease incidence to a lesser extent than intercropping with grain sorghum (Damicone et al 2007 ) .…”

Control of Cucurbit Viruses

“…To be efficient, barrier crops should be tall enough to really interfere with vector movement. Millet or sorghum were efficient in protecting cucurbit crops from potyviruses while barrier crops with a lower canopy (peanut, soybean, or lablab) have been ineffective (Coutts et al, 2011;Damicone, Edelson, Sherwood, Myers, & Motes, 2007).…”

“…Intercropping of pumpkin with sorghum substantially reduced the incidence of the nonpersistently transmitted aphid-borne viruses PRSV and WMV from 96% to 43% (Damicone et al, 2007). Trap cropping may also be a supplement to chemical pesticides in which a preferred plant species (immune to the virus) is used to attract vectors and keep them away from a less-preferred main crop (Shelton & Badenes-Perez, 2006).…”