Interactions of Metarhizium anisoplae and Tree-based Mulches in Repellence and Mycoses Against Coptotermes formosanus (Isoptera: Rhinotermitidae)

• Published in: Environmental entomology 2008-06, Vol.37 (3), p.755-763
• Main Authors: Sun, Jian-Zhong, Fuxa, James R, Richter, Arthur, Ring, Dennis
• Format: Article
• Language: English
• Subjects: Animals; application rate; bark mulches; Biological and medical sciences; biological control; biological control agents; BIOLOGICAL CONTROL—MICROBIALS; conidia; Control; Coptotermes formosanus; entomopathogenic fungi; feed intake; Food Preferences; foraging; Fundamental and applied biological sciences. Psychology; fungal pathogen; fungal repellence; insect behavior; insect control; insect pests; Insect Repellents; Integrated pest control; integrated pest management; Isoptera; landscape mulch management; landscaping; Metarhizium; Metarhizium anisopliae; mortality; mulches; Phytopathology. Animal pests. Plant and forest protection; pine straw; Protozoa. Invertebrates; repellents; Soil - parasitology; Soil Microbiology; subterranean termites; Trees - microbiology; urban areas; wood products
• ISSN: 0046-225X; 1938-2936
• DOI: 10.1603/0046-225X%282008%2937%5B755%3AIOMAAT%5D2.0.CO%3B2

The use of mulch in urban landscapes has increased in the United States for the past decade. Tree-based organic mulches can supply Coptotermes formosanus Shiraki with food, moisture, and shelter. The current research contributes to mulch management technology in termite control. A choice test arena was designed to determine the repellence and mortality caused by commercial mulches treated with different concentrations of the fungus Metarhizium anisopliae (Metschnikoff) against C. formosanus. Each of six tree-based mulches (pine bark, pine straw, bald cypress, eucalyptus, water oak, and melaleuca) was coated with six conidial concentrations ranging from 1 × 103 to 1 × 108 conidia/ml. The foragers of C. formosanus were repelled significantly by the fungal-treated mulch substrates; the proportion of termites on fungal-treated mulch was usually 99% of the termites were killed in test arenas containing a chamber with mulch treated with 107 or 108 conidia/ml. M. anisopliae significantly reduced mulch consumption by 34–71%. Mulch consumption by the termites was negatively correlated with fungal concentration, and the type of mulch also affected consumption. The differences in termite foraging activities, mortality, and food consumption among mulches were usually confounded by differences in fungal concentrations of M. anisopliae. The results indicate that repellence and virulence of M. anisopliae conidia should significantly reduce the suitability of these six mulches as a habitat for C. formosanus.