Fungicide Tolerance and Effect of Environmental Conditions on Growth of Trichoderma spp. with Antagonistic Activity Against Sclerotinia sclerotiorum Causing White Mold of Common Bean (Phaseolus vulgaris)

The present study was conducted to evaluate in vitro compatibility of commonly used agrochemicals as well as the effect of temperature, pH and salt on the growth of six Trichoderma spp. with antagonistic activity against S. sclerotiorum responsible for white mold of common bean. The results revealed that in dual culture, the mycelial growth inhibition of S. sclerotiorum ranged from 83.4 to 87.4 %25. The highest inhibition (87.4 %25) was obtained with isolate T. erinaceum It-58, while the lowest inhibition (83.4 %25) was caused by T. koningiopsis It-21. Except T. asperellum It-13, antagonistic fungi were able to fully colonized pathogen in five days reaching class I antagonism according to Bell scale. The maximum inhibition percentage of volatile (54.07 %25) and non-volatile compounds (68.89 %25) on pathogen was respectively caused by T. asperellum It-13 and T. harzianum P-11. Fungicides affect the growth of Trichoderma differently. No growth was observed while testing compatibility of T. asperellum It-13 and T. erinaceum It-58 with Mancozeb as well as T. asperellum It-13 and T. afroharzianum P-8 with Methyl thiophanate illustrating the absence of compatibility. The excellent growth rate of Trichoderma was found at temperature range of 25ndash%253B30˚C and pH range 4.5-5.5. Apart from T. asperellum It-13, all the isolates were able to grow at NaCl concentrations up to 1000 micro%253BM and were identified as superior salt-tolerant isolates

Response of Congo Grass (Brachiaria ruziziensis L. Germain and Evard) to Nitrogen Fertilization on an Oxisol in Western Highlands Agro-ecological Zone of Cameroon

In the context of climate change, sustainable fertilization management can be achieved by the use of minimum external agricultural inputs capable of generating both economic and environmental benefits. In this regard, a study conducted in western highlands agro-ecological zone of Cameroon revealed the response of Brachiaria ruziziensis (an important cover crop and forage) to a range of nitrogen levels (0, 50, 100, 150, and 200 kgN.ha-1) combined with a constant level of P2O5 (100 kgN.ha-1) and K2O (50 kg%252Fha) evaluated using a randomized complete block design. The findings showed that in a regularly cultivated soil, Congo grass is capable of meeting its mineral needs by searching for them in strata of the soil below the cultural profile (0-25 cm). As a result, in comparison to non-fertilized units (27.75 t.ha-1), fertilized units did not provide a significant dry matter yield (P gt%253B 0.05). Despite the lack of a significant difference, the yield increased with the addition of nitrogen until it reached 100 kg%252Fha, and then decreased until it reached 200 kg N.ha-1. As a result, Congo grass should be used as a biological pump, bringing lixiviated minerals to the surface to favor soil fertility replenishment and shorten fallow period