Because banana plants grow in many places, they can be vulnerable to many different pests. Protecting your banana plant from insect invasion requires intense monitoring. In addition to eating banana plants, some insects will nest and lay eggs on the plants, which exacerbates the damage. Learn to recognize some of the pests you could encounter while growing banana plants.
Aphids -- most specifically the melon aphid -- is extremely destructive to banana plants. The aphids are found in many banana-producing countries, including the United States, Australia, Mexico and South Africa. Melon aphids damage the banana plants by sucking the sap or liquid from the leaves and buds. They can also transmit plant diseases from one plant to another when they bite into the plant to feed. Their sticky excrement can cause sooty mold growth on the banana plant. Melon aphids range in length from 1/16 to 1/4 of an inch and are typically yellow green or brownish green. Chemicals should be used sparingly to control aphids, as the insects quickly develop resistance.
The banana weevil can also cause severe damage to banana plants. The weevil does extensive damage by burrowing and tunneling into the plant roots and stems. The tunnels the insects make also lead to bacterial and fungal infections, which will cause the banana plant's roots to rot and die. Plants weakened by weevil tunnels can blow over in windy weather. Adult weevils are between 10 mm and 16 mm in length and have a hard, beetle-like shell, with a small snout protruding from their heads. The female weevil lays her eggs in holes she chews at the base of the plant, just above the soil. The best way to prevent weevil infestation is to trim any weak or damaged plants and remove any dead plant material from the soil. Mulching around the base of the banana plant can prevent the weevil from finding a suitable spot in which to lay her eggs.
Banana plants are susceptible to damage from both the spider mite and two-spotted mite. These mites are no more than .5 mm long, have eight legs and resemble tiny spiders. Mites suck liquid from the underside of lower plant leaves. Heavy mite infestation results in fruit damage, and the tips of the fruit turn reddish or purple. The spider mite is normally light green, while the two-spotted mite has two black spots on its body. Keep banana plants properly hydrated, as dry conditions promote mite activity. Trim any damaged plants, and pull any weeds nearby.
Nematodes are microscopic worms that burrow into the root system of the banana plant. The worms eat the roots, preventing water and nutrients from being transported to the rest of the plant. The roots develop reddish-brown lesions, and leaves will turn brown and wilt. Plow or till the soil before planting your bananas to kill many nematodes by exposing them to the environment. Trim any discolored leaves of plants suspected of nematode infestation.