Fungi to Control Insects

The diamondback moth has a very high reproduction rate (up to 20 generations a year) and has become resistant to all the currently available insecticides. Caterpillars of this moth feed on cabbages and broccoli causing high yield losses. The cost of trying to control this pest was estimated as US$1 billion in 1997.

The fungus Zoophthora radicans is a common diseases of this moth which infects and kills both adults and caterpillars. When the fungus has killed the caterpillar it grows out of the dead body and actively discharges thousands of infective spores (conidia) for transmission to other caterpillars.

At Rothamsted it is being studied as part of a management strategy to control this insect in combination with the use of sex pheromone attractants. Related fungi are also being investigated to control other insect pests such as aphids.