The Bean Aphid (Aphis fabae) is a notorious insect pest that infests many crops, including green gram (Vigna radiata). It is a small, soft-bodied insect with a pear-shaped body ranging from light green to dark green or black. It feeds on plant sap using piercing and sucking mouthparts, causing significant damage to the plant and reducing its yield. Bean Aphid that belongs to the family Aphididae in the order Hemiptera.
It has a cosmopolitan distribution, including India, Africa, Argentina, China, the United States, Europe, and Australia. Bean Aphid feeds on various host plants, including groundnut, red gram, peas, beans, safflower, lablab, and niger. This insect can cause significant damage to crops by sucking sap from the plants, reducing their growth and yield. Bean Aphids reproduce rapidly, and their population can grow quickly, particularly in warm and humid conditions.
Therefore, early detection and control measures are essential to prevent significant damage to green gram crops. Integrated pest management (IPM) is an effective strategy for managing Aphids in green gram. Crop rotation, resistant varieties, and crop sanitation can lower Aphid numbers. Ladybirds, lacewings, and parasitic wasps can also control Aphids. Insecticides are an alternative because they harm the environment and non-target organisms. If necessary, use low-toxicity insecticides at the recommended rates and timing.
Bean Aphid Management in Green Gram
Identification of Bean Aphid
Bean Aphids (Aphis craccivora) can be identified by their physical characteristics. Both nymphs and adults are small, soft-bodied insects with pear-shaped body that varies in color from yellow-green to black. They have long legs, antennae, and two small, protruding structures called cornicles on their abdomen.
These cornicles secrete a waxy substance that helps protect the Aphids from predators and environmental stress. The dark color of the bean Aphid makes it easier to spot on the host plant. The nymphs of the bean Aphid are similar in appearance to the adult but are smaller and lack wings.
The Life Cycle of Bean Aphid
Bean Aphids (Aphis craccivora) have a short life cycle, averaging 3-8 days. They reproduce parthenogenetically and viviparously, meaning that females give birth to live young without needing fertilization. The greenish-black colored female can produce 8-30 offspring during their 10-12 day lifespan. The offspring are called nymphs, and they undergo four instars before maturing into adults in 5-8 days. The entire life cycle of bean Aphids occurs on the host plant and can result in rapid population growth if left unchecked.
Causes/Conditions Favorable for Bean Aphid Spread in the field
bean Aphids (Aphis craccivora) are a major pest because they flourish in warm, dry climates. They prefer to feed in colonies on the underside of juvenile, well-fed leaves and shoot tips, where they extract plant sap with their piercing and sucking mouthparts. Succulent plant tissues and new growth stimulate population growth. Bean Aphids usually show up in late spring or early summer and do a lot of damage to crops.
Damage Symptoms of Bean Aphid
Bean Aphids (Aphis craccivora), which feed on plant sap, severely damage green grams. Dark-colored Aphids blanket infected leaves, inflorescence stalks, and young pods. Along with feeding, Aphids produce honeydew, a sugary substance that draws ants and encourages the development of dark sooty mold on foliage.