TABLE 1.

M. anisopliae isolates vary in virulence against second-instar BAW and in destruxin production in vitro

ARSEF isolateMetarhizium speciesHost originDestruxins A and B (SEM)aRelative levels of DtxbMean time (days) until deathcMaNPS1 RFLPd
324M. anisopliae var. acridumOrthoptera0.38 (0.20)L5.4aA
703M. anisopliaeLepidoptera0.66 (0.21)L3.6bcB
1015M. anisopliae var. majusLepidoptera0.32 (0.32)L4.1bB
2421M. anisopliaeHomoptera2.97 (0.21)LNTB
297M. anisopliae var. majusColeoptera1.03 (0.22)LNTB
2353Metarhizium sp.Homoptera27.91 (0.94)I4.1bC
1094M. anisopliaeLepidoptera10.35 (1.72)INTC
1080M. anisopliaeLepidoptera12.26 (1.45)I3.9bC
3335M. anisopliae var. anisopliaeColeoptera10.13 (1.13)INTC
808M. anisopliaeColeoptera9.95 (0.41)INTC
2162M. anisopliae var. anisopliaeColeoptera40.75 (2.17)HNTC
2575M. anisopliae var. anisopliaeColeoptera110.41 (13.38)H3.4cC
1095M. anisopliae var. anisopliaeLepidoptera83.54 (3.37)H3.5cB
549M. anisopliaeUnknown59.13 (7.91)HNTC
2547M. anisopliaeColeoptera95.35 (8.47)HNTC
23M. anisopliae var. anisopliaeColeoptera160.34 (14.28)H3.4cC
  • a Estimates are expressed in mg/liter of broth at 14 days postinoculation for destruxins A and B.

  • b Arbitrarily assigned categories of destruxin (Dtx) A and B production. L, low (0 to 5 mg/liter of broth); I, intermediate (>5 to 30 mg/liter of broth); H, high (>30 to 170 mg/liter of broth).

  • c Dosage of ca. 10 spores/mm2. Means followed by the same letter are not significantly different as determined by analysis of variance (F7,347 = 16.0; P < 0.0001; Tukey's test, P < 0.05). NT, not tested.

  • d See Fig. 2. A, double band unique to ARSEF 324; B, single 4.9-kb band typical of most low destruxin producers; C, two bands at 3.2 and 1.7 kb typical of intermediate to high destruxin producers. ARSEF 1095 was an exception to this trend.