Hagus Tarno

Pathogenicity of microorganisms isolated from the oak platypodid, Platypus quercivorus (Murayama) (Coleoptera: Platypodidae)

The oak platypodid, Platypus quercivorus (Murayama), is the most destructive pest of Quercus and related fagaceous species in Japan. To find an effective biocontrol agent, we determined the effectiveness of entomopathogenic microorganisms against P. quercivorus. P. quercivorus-infested Oak (Quercus serrata, Q. crispula and Q. acutissima) logs were obtained from various regions in Japan, and 28 isolates of microorganisms were isolated from P. quercivorus larvae from those logs. Using molecular methods, the microbes were then classified into 18 species. After a bioassay, we found that three fungi, Lecanicillium sp., Isaria tenuipes, Beauveria bassiana, and the bacterium Serratia marcescens had the greatest potential as biological control agents against P. quercivorus. Another bioassay was then performed to determine the effect of spore or cell densities on the pathogenicity of the four microorganisms, and optimum spore or cell densities for the microbes were determined to be 106 and 107/ml. Based on the results and other criteria, we tentatively selected B. bassiana as the best candidate for future use against P. quercivorus larvae.

Distribution of the Endophytic Fungi in Apple Leaves

Endophytic fungi have roles to protect the plant from herbivorous insects and diseases, and to support the absorption process of nutrients needed by plants for photosynthesis. Related to the important role of endophytic fungi, research was aimed to identify fungal endophytes associated with young, mature and old leaves on apple and to evaluate the effect of leaf ages on the abundance and diversity of endophytic fungi. The research was conducted in Biological Control Laboratory, Department of Plant Pests and Diseases, Faculty of Agriculture, Universitas Brawijaya from May to September 2016. Apple leaves sampling was done diagonally, and taken from nine apple trees. Based on macroscopic and microscopic characteristics, 38 isolates were identified. In the old apple leaves, it obtained 17 isolates that consisted of 5 genera, mature leaves obtained 14 isolates consisted of 6 genera, and young leaves 7 isolates obtained consists of 2 genera. The mature leaves have highest abundance and diversity of endophytic fungi compared to young and old leaves. Endophytic fungi apple leaf dominated by Aspergillus. Mature and young leaves were different from old one based on Bray-Curtis similarity.

The Influence of Organic and Inorganic Fertilizers on the Growth and Yield of Green Bean, Phaseolus vulgaris L. Grown in Dry and Rainy Season

Research aimed to study the influence of organic and inorganic fertilizers on growth and yield of green bean ( Phaseolus vulgaris L.). It was conducted in Andisol soil, Batu, East Java, 900 m above sea level, 24-27⁰C for dry season (from May to July 2013) and rainy season (from January to March 2014). A randomized block design was used to arrange five treatments such as 1) no fertilizers applied; 2) five t ha-1 cow manure; 3) 10 t ha-1 cow manure; 4) 50 kg N ha-1, 150 kg P2O5 ha-1 and 50 kg K2O ha-1; and 5) 100 kg N ha-1, 300 kg P2O5 ha-1 and 100 kg K2O ha-1. All treatments of bean was planted in 4 x 3 m2 of plot size and 25 x 20 cm2 of plant spacing. Treatment of 100 kg N ha-1, 300 kg P2O5 ha-1 and 100 kg K2O ha-1 resulted in the highest growth (plant height, leaf number/plant, and leaf area/plant) and yield of pod fresh weight (12.46 t ha-1, in 2013; 16.51 t ha-1, in 2014). The lowest growth and yield was showed by no fertilizer application (6.23 t ha-1, in 2013; 8.36 t ha-1, in 2014).