Insect pests are a serious problem in agriculture. They destroy millions of acres of staple crops such as corn, soybeans, peas, and cotton. Yearly, these pests cause over $100 billion dollars in crop damage in the U.S. alone. In an ongoing seasonal battle, farmers must apply billions of gallons of synthetic pesticides to combat these pests. However, synthetic pesticides pose many problems. They are expensive, costing U.S. farmers almost $8 billion dollars per year. They force the emergence of insecticide-resistant pests, and they can harm the environment.
Other approaches to pest control have been tried. In some cases, crop growers have introduced “natural predators” of the species sought to be controlled such as non-native insects, fungi, and bacteria like Bacillus thuringiensis. Alternatively, crop growers have introduced large colonies of sterile insect pests in the hope that mating between the sterilized insects and fecund wild insects would decrease the insect population. Unfortunately, success has been equivocal and the expense considerable. For example, as a practical matter, introduced species rarely remain on the treated land—spreading to other areas as an unintended consequence. Predator insects migrate, and fungi or bacteria wash off of plants into streams and rivers. Consequently, crop growers need more practical and effective solutions.
One relatively recent solution has been to genetically engineer crops to express plant lipases that have insecticidal properties. Until now, such insecticidal lipases have only been described in certain plants, such as patatin from the potato (U.S. Pat. No. 5,743,477) and pentin from the oil bean tree (U.S. Pat. Nos. 6,057,491 and 6,339,144). However, plant-derived lipases have the inherent disadvantage of having induced natural selection pressure in insects feeding on these plants in the wild. Thus, alternative lipases are needed for insect resistance management. The present invention is useful for avoiding the inherent disadvantage of pre-existing natural selection pressure, while conferring numerous other advantages such as low cost relative to repeated-application pesticides and effective insecticidal properties.