Theory question 104
Crop Pests(a) With the aid of a diagram, describe the life cycle of the variegated grasshopper.
(b) State five ways through which diseases are spread on crop farms.
(c) State six characteristics of a good layer.
Show the model answer
(a) Incomplete metamorphosis: egg → nymph (hopper) → adult. Females lay eggs in pods in moist soil; eggs hatch into wingless nymphs that look like small adults; nymphs moult several times (about five instars), developing wing buds; the final moult gives the winged adult. Diagram: cycle of egg pod → nymphs → adult with arrows.
(b) Any five: wind; water/rain splash; insects (vectors); infected seeds and planting materials; contaminated tools; man (clothes, hands); animals; infected soil and crop debris.
(c) Any six: bright red, large, moist comb and wattles; alert and active; wide, deep, soft abdomen; widely spaced pelvic bones; large, moist, oval vent; good appetite; bleached shanks and beak (yellow pigment used up); clean bright eyes; healthy and not broody.
Name the three stages in order.