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The monoculture of melon in Guatemala has caused the massive appearance of plants with an analogous syndrome for the well-known disease commonly called melon collapse, or vine decline, causing significant losses in crops. Methyl bromide is commonly used to sterilize soil prior to planting in Guatemala, but it must be phased out by 2015. The objective of this study was to evaluate the technique of grafting melon onto hybrids of Cucurbita ( Cucurbita maxima × Cucurbita moschata), as an alternative to using soil disinfectants (such as Metam sodium, 1,3-dichloropropene, and methyl bromide) for the control of collapse. The results suggested that both soil disinfection and grafting were not necessary in these locations, since there were no statistical differences in terms of yields between the treatments and the untreated control. Furthermore, these results demonstrate that decisions to disinfect the soil must be based on the firm identification of the causal agents, in addition to preliminary assessments of yield losses. [ABSTRACT FROM AUTHOR]

Abstract: One of the major challenges of melon (Cucumis melo L.) yield is the decrease of fruit yield and quality caused by soil diseases. Soil disinfection with methyl bromide (MB) has been used to prevent soil-borne diseases damage; however, use of MB is being restricted because this substance damages the ozone layer. Searching for new MB alternatives, field experiments were carried out in open fields in soils infested with Fusarium oxysporum f. sp. melonis, Olpidium bornovanus, and Melon Necrotic Spot Virus (MNSV) in Colima, Mexico, where melons had only been grown previously using soil fumigation with MB. Yield and quality of melon cultivar Cruiser F1 (Harris Moran seed company) grafted on two rootstocks of Cucurbita maxima Duchesne× Cucurbita moschata Duchesne (“RS841”; Séminis seed company and “Shintosa Camelforce”; Nunhens seed company) were evaluated during two consecutive years. Each experiment had five treatments, two of which with non-grafted plants at a density of 18,519plants/ha, with and without MB fumigation. The other three treatments consisted of grafted plants in non-fumigated soil with plant densities of 14,815, 11,111, and 9260plants/ha. The use of melon grafted on “RS841” and “Shintosa Camelforce” rootstocks significantly increased the average fruit weight and the total yield of melons in soil without the need for MB. Grafting may be considered an alternative to MB fumigation. With the use of grafted melon plants, planting density may be reduced by 60%, obtaining higher yields than those obtained from non-grafted plants grown on fumigated land. Fruits harvested from grafted plants had equal firmness than those harvested from non-grafted plants, without affecting the content of soluble solids. [ABSTRACT FROM AUTHOR]