Aphids are piercing-sucking insects of the order Homoptera , suborder Sternorrhyncha , superfamily Aphidoidea . The adult is about 2 mm in size and has different body colors, with common colors being black, yellow, green, and red.
It harms many objects, commonly vegetables, fruit trees, etc. Aphids are small and like to live in relatively hidden places such as tender shoots, backs of leaves, flower buds, and fruits. Aphids can reproduce both parthenogenetically and sexually. Spring and autumn are the seasons when female insects reproduce in large numbers, especially during periods of high temperature and little rain. If the management is not good, aphids will explode and easily cause a great impact, especially on plant growth. Since budworms continue to shed their skin and grow, in the early stages you can see shed shells with white debris attached to them around the environment.
Common aphid species
1. Cotton Aphid
Scientific Name: Aphis gossypii Glover, 1877
English Name: Cotton aphid
Appearance characteristics: The wingless viviparous insects are 1.5~1.8 mm long. The body color varies with the season, temperature and host, generally light green to dark green. The abdominal tube is tubular and black, longer than the tail fin, and the tail fin is nipple-shaped. The wings of the winged adults are transparent, with yellow-brown veins and gray or light brown wing spots.
Damage: This insect occurs all year round and can be seen in all seasons, with about 20 generations occurring each year. This insect is omnivorous and has a wide range of host plants, including common cruciferous vegetables, beans, melons, fruit trees, etc.
Aphids will continuously secrete nectar from their tails and allow ants to eat them in exchange for the ants' protection. Therefore, many times when you see ants, you know there are aphids. Aphids and ants have a mutually beneficial symbiotic relationship, providing benefits to each other in exchange for survival benefits.
2. White-tailed red aphid gold Also known as: lettuce aphid
Scientific name: Uroleucon formosanum (Takahashi, 1921)
Appearance characteristics: Wingless larvae have red bodies, but the middle part of the body and antennae are black. Host plants include lettuce, escarole, and citronella.
3. Podocarpus aphid
Scientific name: Neophyllaphis podocarpi Takahashi, 1920
Appearance characteristics: Wingless larvae with bodies covered with white wax powder. Host plants include Podocarpus, Bamboo Cypress, etc.
Biological control
Predatory natural enemies include ladybugs, lacewings, hoverflies , etc.
Ladybug larvae feed mainly on aphids .
Ladybug stages from larva to adult .
The larvae of lacewings - aphid lions, mainly feed on aphids. They attach themselves to objects with silk stalks . Their eggs are oval and about 1 mm long.
Yellow-bellied narrow-mouthed hoverfly , the adult hoverfly lays eggs on plants infested with aphids, and the larvae can feed after they are born .
Planting Blood-flower ( Asclepias curassavica ) can attract a variety of natural enemies of aphids, such as ladybugs, lacewings, and aphid flies. Planting it in the fields can suppress the population of aphids and avoid sudden outbreaks that harm crops.
Physical prevention
You need to pay attention to whether you are over-fertilizing. Too much nitrogen fertilizer can cause an aphid outbreak.
Keeping the environment well ventilated and thoroughly weeding will help reduce the spread of aphids.
Other material prevention
Taking advantage of the fact that aphids hate light, cover the fields with reflective objects to drive away the aphids.
Hanging yellow sticky insect paper can attract aphids and kill them.
References:
Taichung District Agricultural Monthly (Taichung District Agricultural Improvement Station)
https://info.organic.org.tw/%E8%9A%9C%E8%9F%B2/
https://www.hdares.gov.tw/ws.php?id=9543