A disease in an insect may be produced by any circumstance that causes such an abnormal state. Physical injuries, chemical injuries, nutritional deficiencies, genetic abnormalities, and neoplasms may result in a disease state. With the exception of sterility, noninfectious diseases are seldom considered a component of a biological control program, but when evaluating individual insects or a population of insects for the underlying causes of disease, researchers should be aware of several possibilities other than infectious diseases. Insects are naturally somewhat protected from injury by the cuticle, tracheal system, and physiological adaptations. Nevertheless, injuries occur and include distention (blockage), trauma such asabrasions/crushing, and open wounds. Responses to physical injury include: release of haemokinin (injury factor) into the hemolymph, which speeds the heart rate, mobilizes hemocytes, and stimulates RNA synthesis. It also causes hemocytes to increase in motility and adhesiveness. Insecticides may be physical or protoplasmic poisons, metabolic inhibitors, hormone mimics, stomach poisons, or neuroactive agents. Most synthetic insecticides are neurotoxins. Deviations from basic conditions needed for attraction to and survival on a food source can lead to nutritional disease. Improper balance of nutrients, amino acids, proteins, fats, carbohydrates, vitamins, inorganic ions, etc. can cause various symptoms of nutritional disease. Symptoms in larvae include severely affected growth rates and development. Often adults have deformed wings, and mating and egg production may be seriously affected.