Efeito da temperatura do solo na infectividade e reprodução det Meloidogyne javanica e Heterodera glycines em cultivares de soja

Abstract

RESUMOA infectividade e a reprodução de Meloidogyne javanica e de Heterodera glycines, em cultivar suscetível e resistente de soja, diferiram, de acordo com a temperatura do solo. A 28 o C o número de massas de ovos, total de ovos, de fêmeas e a porcentagem de sucesso de parasitismo dos juvenis do segundo estádio (J2) em cada cultivar (suscetível e resistentes) de soja infestada com M. javanica foram, significativamente maiores, comparados com as demais temperaturas (32º C, 26º C, 24º C e 20º C). Entretanto, a soma de juvenis do terceiro e quarto estádios (J3 e J4) foi maior em todas as cultivares, quando a temperatura submetida às plantas inoculadas com M. javanica foi de 20º C comparada com as demais temperaturas. A capacidade reprodutiva da fêmea (ovos por fêmea) de M. javanica foi sempre maior na cultivar suscetível em cada temperatura testada, porém, significativamente maior na cultivar suscetível colocada a 32º C comparada com as demais temperaturas. Nas relações H. glycines e soja, as temperaturas testadas proporcionaram valores semelhantes para a população total (fêmeas e cistos) na cultivar resistente. Na cultivar suscetível, a temperatura de 28º C aumentou significativamente o número de fêmeas, total de fêmeas e cistos e a porcentagem de parasitismo de J2 de H. glycines, comparada com todas as demais temperaturas. Termos para indexação: Nematóides de galhas, parasistismo, Glycine max. ABSTRACTThe infectivity and reproduction of Meloidogyne javanica and Heterodera glycines in susceptible and resistant soybean cultivars differs according to soil temperatures. At 28 o C the egg-mass number, total eggs, and females, and percentage of parasitism success of second stage juveniles (J2) in each cultivar (susceptible and resistants) of infested soybean with M. javanica were significantly greater when compared to other temperatures (32º C, 26º C, 24º C and 20º C). However, the sum of third and fourth juvenile stages (J3 and J4) was greater in all cultivars when M. javanica inoculated plants were submitted to 20 o C. The female reproductive capacity (eggs per female) of M. javanica was always greater on susceptible cultivars in each tested temperature, but significantly greater in the susceptible cultivars submitted to 32 o C as compared to other temperatures. On the interaction between H. glycines and resistant soybean cultivars, the different temperatures resulted in similar values for the total population (females + cysts no.) on the resistant cultivars. On susceptible cultivars 28º C increased significantly the number of females, total females + cysts and the percentage of J2 parasitism of H. glycines as compared to all other temperatures.

Infectivity and reproduction of Scutellonema bradys on weeds and cultivated plant species

“…The maximum root penetration rate between nematodes inoculated and recovered found in our study (80% in 16 days) was similar to the numbers found for P. penetrans (68-81% in 5 days) in soybean roots (Lindsey & Cairns, 1971) and higher than the values encountered for the endoparasitic species M. javanica {2,A%) and Heterodera glycines {Al-52%) in soybean (Campos et al, 2011).…”

Nematicidal effect of Crambe abyssinica leaf extracts to Meloidogyne javanica on tomato

“…However, at this same time, there was a reduction in the mass number of eggs by way of root+leaf and root+soil+leaf, so it can be concluded that the extract has acted in reproduction, once feeding sites were induced. According to Campos et al (2011), M. javanica can penetrate at the roots and form feeding sites, however, it has not been ensured that it will reproduce, because the nutritional status influence the reproduction. Continuous stimulation of the nematode for induction and maintenance of giant cells is necessary, otherwise the cells be atrophied (Reddigari et al, 1985).…”

Reproduction of Meloidogyne javanica in crambe plant and influence on crop yield and oil content

“…usually has high activity in the soil and roots under high temperatures, and its ideal temperature for reproduction is 25°C. However, species such as M. incognita and M. javanica cannot survive at temperatures lower than 10°C (Ritzinger et al, 2010;Campos et al, 2011). Campos et al (2011) reported that the reproduction of M. javanica in soybean plants increased at a temperature of 28°C, both in resistant and susceptible varieties.…”