Biological Control of Rice Black Bug, Scotinophara coarctata (FAB.), in Leyte

Mandras, Bimbo; Po, Mylene Milan

Biological Control of Rice Black Bug, Scotinophara coarctata (FAB.), in Leyte

2004

Mandras, Bimbo | Po, Mylene Milan

Metarhizium anisopliae (Metch.) Sorokin was applied in three different methods: spray, through irrigation and broadcast. Spraying was the most effective method of applying M. anisopliae to reduce rice black bug population as evidenced by the significantly higher percentage of infected rice black bugs collected from plots sprayed with spore suspension of M. anisopliae than in plots applied with same fungus through immersion of the medium and broadcasting them regardless of the time of sampling. The effectiveness of spraying over the other two methods was the efficient deposition of spores on the plant surface or on the cuticles of the rice black bug themselves during application allowing greater chances of pick up by the insect which resulted in higher percentage (90%) infection of rice black bug on the sprayed plot. M. anisoploae had no effect on fecundity and hatchability of the eggs or rice black bug suggesting that the fungus was not transovarially transmitted. Percentage nymphal infection by M. anisopliae was very low. The results of the study also indicate that application of M. anisopliae in the field did not affect the egg parasitoid.

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