Humberto Vaquera-Huerta

A Goodness-of-Fit Test for the Gumbel Distribution Based on Kullback–Leibler Information

A goodness-of-fit test for the Gumbel distribution is proposed. This test is based on the Kullback–Leibler discrimination information methodology proposed by Song (2002). The critical values of the test were obtained by using Monte Carlo simulation for small sample sizes and different levels of significance. The proposed test is compared with the tests developed by Stephens (1977), Chandra et al. (1981), and the test given by Kinnison (1989) in terms of their power by considering various alternative distributions. Simulation results show that the Kullback–Leibler information test has higher power than some of the studied tests.

Biocontrol of Phytophthora parasitica and Fusarium oxysporum by Trichoderma spp. in Hibiscus sabdariffa plants under field and greenhouse conditions

The efficiency of the biological control agent Trichoderma spp was tested against Phytophthora parasitica and Fusarium oxysporum in Roselle plants under field and greenhouse conditions. Under field conditions, three Trichoderma doses were applied to the base of the plant, and azoxystrobin and benomyl were applied at 30 and 60 days after planting. Also, 30 day-old plants were inoculated with 7 g of corncob/Trichoderma under greenhouse conditions, and inoculated with F. oxysporum and P. parasitica 3 or 4 days later. Field results showed that Trichoderma longibrachiatum-treated plants had 15% less incidence of black shank, and in one of the experiments, calyx dry weight was higher. Under greenhouse conditions, plants inoculated with Trichoderma gamsii and T. longibrachiatum had between 20 and 30% less incidence of F. oxysporum and P. parasitica, respectively. Both Trichoderma species increased fresh and dry plant weight, and T. gamsii also increased plant height. In general, T. gamsii and Trichoderma virens increased height, fresh and dry weight of Roselle plants infected with F. oxysporum. n n xa0 n n Key words: Trichoderma virens, Trichoderma longibrachiatum, Trichoderma asperellum, Trichoderma gamsii, Roselle.