Aspidiotus is a genus of armored-scale insects that cause severe damage by piercing and sucking their host crops. They reproduce sexually by producing eggs that hatch into crawlers and crowlers that develop into sedentary adults. Their life cycles are typically around one month and their only mobile stage is the crawler stage. They prefer perennial than annual crops because perennial crops provide continuous source of food without a need for the crawlers to travel long distance once they have established. 

Root crops have modified roots to function as storage organs, while tuber crops have modified stems or roots to function as both storage and propagation organs. As such, the modified roots of root crops cannot propagate new crops, whereas the modified stem or roots of tuber crops can propagate new crops. Examples of root crops are potato, sweet potato, and dahlia; examples of tuber crops are carrot, sugar beet, and parsnip.

Fred Benu I presume you didn't finish your answer and were about to mention pesticides to kill these insects, being the toxins left in the soils