Exploitation of trichoderma species on the growth of Pythium Aphanidermatum in Chilli

Damping-off of chilli caused by Pythium aphanidermatum is a major nursery disease in vegetables. In vitro experiments evaluated the effect of eight isolates of Trichoderma species (from chilli rhizosphere) were tested against P. aphanidermatum. All the Trichoderma species had varied antagonistic effects against the pathogen. Among them, TVC3 recorded maximum growth inhibition of P. aphanidermatum and produced more amounts of volatile and non-volatile metabolites. The culture filtrate of the Trichoderma isolate TVC3 recorded complete inhibition on the mycelial growth of pathogen at 15 percent concentration. Moreover, chilli seeds treated with culture filtrate of the isolate TVC3 recorded maximum germination percentage, shoot length, root length and vigour index of chilli. The study identified the Trichoderma isolate (TVC3) performed well in inhibiting the mycelial growth of pathogen as well as increased the plant growth in chilli.

Abilities of Trichoderma Species to Persist within Maize (Zea mays) Stem Long after Inoculation.

Different Trichoderma species were examined for their abilities to persist within the maize (Zea mays) stem at different points above and below inoculation points. Different Trichoderma species were isolated from different parts of the maize (Z. mays) plant and its rhizosphere. They were later sent to International Mycological Institute, England for identification. Maize seeds (DMR-LSRW) were planted in pots in the screenhouse. Four weeks after planting, each of the Trichoderma species was inoculated into the stems of the potted plants at the 2nd internodes using the toothpick method. Toothpicks dressed with sterile distilled water served as control. Cut sections of the inoculated stems were examined for presence or absence of the inoculated Trichoderma species at different points far from the inoculated point in the upper and lower internodes after 2, 3, 4, 5 and 6 weeks of inoculation. Ten Trichoderma species were identified; these include five strains of T. pseudokoningii, three strains of T. harzianum, T. hamatum and T. longibrachiatum. All the Trichoderma species were able to move within the stem tissues into the upper and lower internodes. All of them were re-isolated at distant points from inoculation point in the upper and lower internodes even after 6 weeks of inoculation. T. pseudokoningii strain 2 and T. harzianum strains 1 to 3 had the best endophytic movement into the upper and lower internodes. T. hamatum and T. longibrachiatum had the weakest movement into the upper and lower internodes. All the Trichoderma species could thus be said to possess the abilities to persist (endophytic capability) within the maize (Z. mays) stem. T. pseudokoningii and T. harzianum could also be said to be among the best species in the genus Trichoderma with good prospect of biocontrol potential.

Breeding and Screening of Lentinula edodes Strains Resistant to Trichoderma spp

Trichoderma spp. cause large crop losses of the cultivated shiitake mushroom, Lentinula edodes. We bred several shiitake strains that are resistant to Trichoderma spp. using di-mon mating to establish a useful method for controlling the greenmold disease. We examined the competitive ability of L. edodes against Trichoderma spp. using a dual culture system to select resistant strains. By screening Trichoderma-resistant strains, we found that among 11 parental strains, 4 strains, including KFRI 36, were confirmed resistant strains. They showed especially strong resistance to T. harzianum, which formed deadlock after mycelial contact and then invaded into the territory of T. harzianum. KFRI 171 also showed resistance to T. atroviride strains. Among 13 strains, which were made by hybridization of shiitake strains, 5 were confirmed to be resistant to Trichoderma, including KFRI 58-1. Their resistance was not correlated to the resistant activity of their parents' strains. Two strains lose resistance and two strains acquire resistance compared to their parents' strains. In SEM observation, the mycelium of L. edodes at the interaction zone of Lentinula-Trichoderma was rugged and swollen by T. harzianum.