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  • Author or Editor: Jaime Molina-Ochoa x
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Low organic matter in soil is a large problem in crop production around the world because it affects physical, chemical, microbiological, and morphological properties. On the other hand, regions with agro-industry generally generate waste that can cause some level of contamination. Therefore, it is necessary to find some use for this kind of waste. This study was done to evaluate the effect of lemon industrial waste on tomato (Lycopersicum esculentum Mill.), growth in a saline soil. The experiment was conducted under greenhouse conditions. Soil samples were taken from 0- to 20-cm depths at the El Chococo ranch, located at 18°47'N and 103°55'W. Four treatments were imposed: 0 (0), 600 (1), 1200 (2), and 1800 (3) m3/ha. Soil in treatments was incubated at ambient temperature for 40 days. Tomato seeds were germinated for 30 days and later transplanted to plastic bags containing treatments. After transplant, tomato plants were grown during 40 days, after which was measured: high plant, dry and fresh weight, aerial, and radicular biomass and foliar area. Treatments were distributed under randomized design, and Tukey's (0.05) separation means was performed. Organic matter, pH, and CE in soil before treatment application was 1.01%, 8.5, and 7.6 dS/m respectively (in 1:5 soil: water ratio). After application, OM increased until 3.7% in treatment 3. pH and CE decreased to 5.5 in treatment 2, and 1.57 dS/m in treatment 0. All data measured in plants had the highest values in treatment 1, and all plants died in treatment 0. We believe that is necessary to do this experiment in the field to obtain additional data.

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Scyphophorus acupunctatus is the main pest of Agave tequilana. Its adults are vectors of Erwinia carotovora, which causes plant destruction. The susceptibility of S. acupunctatus larvae to various strains of entomopathogenic nematodes has been demonstrated previously (Molina et al., 2004). In the current paper, the use of seven different concentrations: 0, 10, 20, 50, 100, 200, and 500, of infected juveniles per larva in petri dishes containing a filter paper against Steinernema carpocapsae strains All, Ca, and Fl, and also against native insolated N1, N2, N4, belonging to the genera Steinernema sp. The studies were conducted under laboratory conditions to determine the susceptibility of S. acupunctatus larvae to entomopathogenic nematodes. One hundred percent mortality of S. acupunctatus larvae was achieved by S. carpocapsae strains All, Ca, and Fl with exposure to 100 infected juveniles. In the case of native isolates, N2 registered 95% mortality, and for N4 and N1, mortality registered was 75%. An analysis of variance was conducted in order to determine whether strain or isolate had the highest virulence against S. acupunctatus larvae. Means for S. acupunctatus larvae by entomopathogenic nematodes presented significant differences (F = 57.01; df = 55, 223; P < 0.0001), resulting in two levels. At the first level, S. carpocapsae All, Fl, and Ca are statistically the same as isolate N4. At the second level, the isolates N4 and N1 are statistically the same. The results indicate the high susceptibility of S. acupunctatus larvae. The infectivity of native isolates as well as S. carpocapsae strains All, Fl, and Ca are associated with the symbiotic bacterium Xenorharbdus sp., suggesting they have potential for use against S. acupunctatus larvae.

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