Infesting microorganisms

The lethality of ionizing radiation is proportional to the complexity of the organism. Humans, for example, cannot survive more than 800 r., but it may take 2 million r. to inactivate a microorganism. Insect life, of the type which infests field crops, show intermediate stability. Information gleaned from the best available sources (B15, Bl, H9) indicate that a 1000-r. exposure will kill all eggs, 1300 r. will kill all larvae, and 3,000 r. will destroy all young pupae. The resistance of insects to radiation increases with age. For example, to kill some adult species requires 50 to 60,000 r. Adult flour beetles succumb at 10,000 to 16,000 r. 

Many foods contain preservatives that prolong the shelf life and/or combat infestations by insects and microorganisms. Sulfur dioxide (S02) is probably one of the oldest preservatives. For centuries, people found that if the summer harvest of fruits is to be preserved and stored for the winter months, a drying process can accomplish the task. Raisins, dates, dried apricots, and prunes are still sun-dried in many countries. The drying process increases the sugar concentration in such dried fruits, and bacteria and most other microorganisms cannot use the dried fruit as a carbohydrate source because of the hypertonic (hyperosmotic) conditions. 

Prevention and Control Plant resistant cultivars, when available. Rotate crops. Avoid spreading soil from infested to noninfested areas. Soil solarization helps to reduce nematode populations. Or try a cover crop of marigolds, and turn them into the soil at the end of the season. Incorporate plenty of organic matter into the soil to promote natural nematode-controlling microorganisms. Drenching the soil with neem may also help. 

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