How Pests Feed: Agriculture
A pest is “a plant or animal detrimental to humans or human concerns (as agriculture or livestock production)”; alternative meanings include organisms that cause nuisance and epidemic disease associated with high mortality (specifically: plague). In its broadest sense, a pest is a competitor of humanity. In the past, the term might have been used for detrimental animals only, thus for example, causing confusion where the generic term ‘pesticide’ meant ‘insecticide’ to some people. It is any living organism which is invasive or prolific, detrimental, troublesome, noxious, destructive, anuisance to either plants or animals, human or human concerns, livestock, human structures, wild ecosystems, etc. It is a loosely defined term, often overlapping with the related terms vermin, weed, plant and animal parasites and pathogens. It is possible for an organism to be a pest in one setting but beneficial, domesticated or acceptable in another.
Pests such as aphids, whitefly, and red spider mite use needlelike mouth-parts to pierce plant stems and suck sap, resulting in reduced vigor and growth distortions (as in aphid damage, shown here). Bacterial infections can also enter the plant via the wounds.
Sapsuckers can transmit viruses, and their waste (honeydew) provides a food source on which molds thrive.
Many insect larvae, including some moth caterpillars, beetle grubs such as wireworms (shown here in a potato), vine weevil, cabbage root fly, and parasitic nematodes known as eelworms, graze on roots. damage
restricts nutrient and water uptake, restricting growth and causing wilting; root crops may be rendered inedible.
Many caterpillars (here of a sawfly), adult beetles and their grubs, and of course slugs and snails, graze on leaves and sometimes stems. other larvae mine or tunnel leaves. Leaf damage reduces the area where photosynthesis operates, sapping the plant’s strength and reducing fruit set. These larvae are about 50 mm in length when fully grown. They are black on top, with a light line down the back bordered on each side by tan to brown lines. Their bodies are sparsely covered with fine, light brown hairs.
Earwigs, psylla, thrips, and Japanese beetles (shown) feed on flower heads and buds. damage may be significant, but is often only cosmetic.
Many bird species strip fruit trees and bushes of flower buds in late winter and early spring, when food is scarce.
The presence of some fly and wasp larvae, as well as mites, causes distortions of growth known as galls;
this is an “oak apple” caused by a tiny wasp. Galls are usually harmless, but some gall-formers transmit viruses.
Some caterpillars, beetle grubs, and fly larvae feed on developing fruits; birds and wasps (shown) feed on ripening fruit. damage is usually limited, but the soiled fruit can be unpalatable, and other infections may enter the wounds.
Published: Zarai Media Team