Muskmelon (Cucumis melo L.) is the major cucurbit crop in the Colima state, Mexico. The use transparent plastic mulch continues to increase in that region for high production technology systems of muskmelon, and more recently floating rowcovers were introduced to protect cucurbits from insects (direct pests or vector of viruses) and to increase yield of cucurbit crops. During 1993, yield was evaluated of three cultivars of muskmelon (`Crushier', `Laguna', and `Durango') growing on transparent polyethylene mulch alone or with floating rowcover. The cultivar Crushier showed the higher yield 40 ton/ha (77% for export market), followed by `Durango' with 28.5 ton (77% for export quality) and `Laguna' with about 23 ton (only 40% of export fruit). There was no significant difference in yield between cultivar growth on transparent mulch plots alone and combined with floating rowcover. Also, floating rowcover excluded (until perfect flowering) beetles leafminers, sweetpotato whitefly, and aphids, reducing the use of insecticide by 50%.
Zucchini yellow mosaic virus (ZYMV) infection causes heavy losses in cucurbit crops grown in the Mediterranean, Central Europe, the United States, and Mexico. Recently, ZYMV was found affecting muskmelon (Cucumis melo L.) in Colima, Mexico. An experiment was carried out under dry tropical conditions with the objectives: 1) to determine the effect of ZYMV on flowering and yield of muskmelon cv. Primo, and 2) to evaluate its transmission by some aphid species. Perfect and staminate flowers were significantly reduced when ZYMV was inoculated during vegetative growth, flowering, and fruit set. ZYMV affected yield when it was inoculated from vegetative growth to flowering and fruit set. In plants inoculated during vegetative growth the yield was null, while those inoculated at early flowering and fruit set the yield was reduced by 80% and 49%, respectively. The yield was not affected when ZYMV was inoculated on fruit growth. The aphid Myzus persicae, Aphis gossypii, A. spiraecola, and Uroleucon ambrosia-transmited ZYMV from Cucurbita pepo to Cucumis melo; but Aphis nert, did not.
The effect of floating rowcover and transparent polyethylene mulch was evaluated on insect populations, virus disease control, yield, and growth of muskmelon (Cucumis melo L.) cv. Durango in a tropical region of Colima state, Mexico. Aphids (Aphis gossypii Glover and other species), sweetpotato whitefly (Bemisia tabaci Gennadius), beetles (Diabrotica spp.), and leafminer (Lyriormyza sativae Blanchard) were completely excluded by the floating rowcover while the plots were covered (until perfect flowering). Transparent mulch reduced aphids and whitefly populations, but did not show effect on leafminer infestation. The appearance of virus diseases of plants was delayed for 2 weeks by floating rowcover with respect to control (bare soil). Also, the transparent mulch reduced the virus incidence. The yield and number of fruit were positively influenced by floating rowcover and transparent mulch. Plot with transparent mulch combined with floating rowcover yielded nearly 4-fold higher (50.9 t·ha–1) than that plots with bare soil (13.1 t·ha–1). The yield from plots with floating row cover on bare soil was of 38.3 t·ha–1, while in the transparent mulch plots it was of 23.1 t·ha–1. The results of this work shows the beneficial effects of floating rowcover and transparent mulch in dry tropical conditions.
In Central Pacific region, Mexico, are cultivated around 17,000 ha of cucurbitaceous. This crops are affected by wilt, this disease is caused by Fusarium oxysporum (F.o.) Schlechtend. Some farmers are using resistant varieties to this disease, but resistance is different to each cultivar. Soil fumigation is other way to control this pathogen. Soil solarization is a new alternative for Fusarium oxysporum control. The objective of this research was to evaluate the effect of soil solarization on Fusarium oxysporum for wilt control in muskmelon crop in Colima State. The experiment was carried out under field conditions, using Cantaloupe melon (Cucumis melo L.) Cv. Ovation, in Ixtla-huacán municipality during November-December. Clear plastic was used (thickness 110). Evaluation of solarization periods were 0, 10, 20, and 30 days. Experimental design was full random blocks, with four replications. Evaluated variables were: soil temperature at 5-,10-, and 20-cm soil depth, propagule number of Fusarium oxysporum in soil, wilt incidence and yield. For determine Fusarium oxysporum survival, a strain isolated from infected plants was used. Fungi was introduced in cloth bags, containing 10 gr of sterile sand with 10 mL of a suspension of 19,000 conidia/mL. Later were introduced four cloth bags per treatment at 5-,10-, and 20-cm soil depth. When plants were harvested, was taken the sick plants percentage. Results shown that soil solarization periods had not an effect on the propagule number at the soil depth for the solarization periods. Also soil solarization had not and effect on plant yield. Is necessary to do the same experiment during different season, as June-July or September-October, to have a higher soil temperature and humidity.
Soil solarization is used for soil born pathogens control, as a result of temperature increase in soil, around 10 °C higher than in not solarized soils. In Mexico, is mostly used to decrease cost to control of different diseases that affect to melon crop, one of them is caused by Fusarium oxysporum f. sp. melonis (L & C) Snyder & Hansen, which is characterized by wilt and yellowing in melon plants. The objective of this assay was to evaluate the effect of heat on infective capacity of F. oxysporum f. sp. melonis in melon plants and its reproduction capacity after to be under different periods of heat under laboratory conditions. Isolated was taken from melon plants from Carmelitas Ranch in the Colima Municipality. Inoculation was 1 × 10-6 conidia concentration. Cloth bags, with 20 g of inoculated soil, were introduced at 9 cm depth in metallic pots (16 cm diameter and 18 cm depth) containing 4 kg of not inoculated soil during 24, 48, 72, 96, and 120 h, with 6 replications. After each period, 1 g was taken from the cloth bags used in heat treatments, later was diluted in 50 mL of distillated water, and petri dishes containing PDA, were inoculated with 1 mL from that dilution and inoculum viability was registered at 96 h after incubation. Parameters evaluated were: mycelium growth, propagule number, and conidia number. Results showed a positive effect to control of Fusarium oxysporum f. sp. melonis, in treatments with a higher heat period, respecting to the control. Is necessary to evaluate this technique under field conditions during summer season.
In the Pacific Central region of Mexico, 17,000 ha are cultivated with cucurbitaceous crops. Most are affected with wilt caused by Fusarium oxysporum f. sp. melonis. The use of fungicides, such as methyl bromide, for soil disinfecting is a common practice; however, this practice has adverse effects on beneficial microorganisms, and soil is rapidly infected again. Soil solarization is a sustainable alternative, and it is feasible to be integrated in production systems. It has been used to delay the establishment of symptoms and to reduce the incidence of fusarium wilt in watermelon fields. The objective of this study was to evaluate the effect of soil solarization and methyl bromide on control of fusarium wilt on cantaloupes in western Mexico. The experiment was conducted in the Ranch Fatima located in the municipality of Colima. Severe wilt incidence and damage were previously observed in the cantaloupe cultivar Impac. Dripping irrigation system was used. Treatments established were: 1) solarization; 2) solarization + vermicompost; 3) solarization + chemical products [methyl bromide + chloropicrine (98/2%)]; 4) methyl bromide; and 5) control (without solarization or chemicals). Soil solarization was done during the 6 months before planting using clear plastic mulching (110 thick). A completely randomized design with five treatments and four replications was used. Six beds, 10 m long and 1.5 m wide, were used as experimental unit. Variables registered were: leaf area, leaf number, dry and fresh weight, propagule number, soil temperature, number of diseased plants showing wilt symptoms, and yield. Treatments 1 and 3 exhibited the highest agronomic variable values, and best control of fusarium wilt and fruit yields.
Development of resistance to chemical pesticides has been reported in about 150 plant pathogenic species, mostly fungi. Biocontrol of plant pathogens is an alternative to chemical pesticides. Actually, there are products formulated with beneficial microorganisms, such as mycorrhizal fungi, rhizobacteria, antagonistic fungi, and others. The objective was to evaluate the development of Fusarium oxysporum f. sp. melonis (FOM) on melon plants inoculated with commercial biological formulations based on beneficial microorganisms. Twelve treatments were evaluated: T1) VAM media nursery + FOM; T2) Hortic Plus + FOM; T3) BioPak F + FOM; T4) Glomus intraradices + FOM; T5) FOM; T6) control; T7) VAM media nursery; T8) Hortic Plus; T9) BioPak F; T10) Glomus intraradices; T11) FOM + Mancozeb wp80; and T12) FOM + BioPak F. The melon cultivar used was `Colima' (Peto Seed Co.). Seeds were planted in Styrofoam growing containers containing coconut fiber powder as substrate. One seed was planted per cell and maintained until transplanting. Plants were transplanted to pots containing sterile soils 13 days postemergence. Inoculation of treatments with Fusarium was made with a concentrated suspension at 1 × 106 conidia/mL. For inoculation with beneficial microorganisms, manufacturer specifications were followed. A completely randomized design with 12 treatments and 12 replications was used to estimate the incidence of Fusarium, number of leaves, leaf area, root biomass, and percentage of roots colonized by mycorrhizal fungi. Overall, T10 showed the best behavior in all variables. Inoculation of cantaloupe plants with Fusarium affected their performance, but those treatments including mycorrhizal fungi enhanced their performance withstanding the damage by Fusarium.
Melon wilt (MW) is one of the main diseases affecting the cucurbitaceous crops in the Pacific Central region of Mexico. The use of resistant varieties is the most effective strategy to reduce the damage caused by MW; however, variety performance depends on the fungal race occurring in the field. The use of fungicides, such as benzimidazols and methyl bromide, is a common practice, but there are contamination concerns, and a search is on for alternatives to diminish the negative effects on the agro-ecosystem. The aim was to determine the effect of the application of soil amendments and mulching on the incidence of MW, and on melon yield. Soil amendments incorporated were: rice straw (3 t·ha-1); compost 1, prepared with chicken and bovine manure, and banana and orange wastes (5.7 t·ha-1); compost 2, prepared with bovine and horse manure, coconut wastes and grasses (8 t·ha-1), vermicompost (3 t·ha-1), and a control. All treatments were established using transparent mulching during 21 days. The number of MW propagules in amended soils were similar at 5, 10, and 20 cm deep, but the percentage of diseased plants was higher (4.5%) in the control, which could be caused by the incidence of other fungi propagules, perhaps antagonistic, that contributed in diminishing the MW when compared with the control. The fruit weights and fruit sizes were not different between treatments on small (21–30 sizes), medium (15–18 sizes), and large (9–12 sizes), but total fruit numbers were 1.15-, 1.07-, 0.99-, and 1.09-fold higher when compared with the control. The application of soil amendments affected the antagonistic fungal populations even when it did not affect the cantaloupe yield. We suggest that soil amendments will improve soil fertility and increase melon yields, and studies are currently running.