Contact - the pesticide must come into contact and penetrate the pest. This can happen by droplets landing on the pest or the pest walking or crawling on the substance.
Stomach poison - The insect needs to ingest the poison.
Non-systemic - the pesticide is absorbed by the plant but is not transferred into its vascular system. Animals are affected by eating the plant parts that have been contacted by the pesticide.
Systemic - the pesticide is absorbed and carried around the plant by the vascular system and the animal eats the plant parts. These pesticides are useful when:
plants have thick foliage
when rain or watering may wash the pesticide off and reduce its effectiveness
or when the pest may have a protective covering or be difficult to see.
