HPIPM:Aphids Spinach

Taxonomy

Domain	Eukarya
Kingdom	Animalia
Phylum	Arthropoda
Subphylum	Hexapoda
Class	Insecta
Subclass	Pterygota
Infraclass	Neoptera
Superorder	Paraneoptera
Order	Hemiptera
Suborder	Sternorrhyncha
Infraorder	Aphidomorpha
Superfamily	Aphidoidea
Family	Aphididae
Subfamily	Aphidinae
Tribe	Macrosiphini
Genus	Myzus
Subgenus	Nectarosiphon

Scientific Name

Myzus persicae

Common Name

green peach aphid

Author: Whitney S. Cranshaw

Identification (and life cycle/seasonal history)

Adult aphids, or plant lice as they are sometimes called, are usually green, but can be brown, yellow, pink, or black, depending upon the species. They tend not to get any larger than 1/16 to 1/8 of an inch in total body length. In general, a female (males are often unknown or absent in several species) gives birth to another female. This is called parthenogenesis. Ovoviviparous is the term used when the egg stage is kept within the female and the young insects emerge alive. Internally, each immature aphid is already reproducing another female inside her, so when you kill one aphid, you could be killing three or four generations at once! Within one to two weeks, a single aphid may produce 50 to 100 offspring. All of these aphids are wingless, even when they finally reach maturity. Winged aphids, or alates, begin to appear in the population when overcrowded conditions occur. These alates can fly to other plants and are called the spring migrants.

Towards the end of the growing season, the aphids use the light and temperature changes as a cue to produce an all winged generation that contains both males and females known as the fall migrants. The females of this generation then give birth to a new batch of females that are wingless and they must mate with the winged males from the generation before them. These are true females, and after mating they usually lay one to four eggs in a sheltered place on or near the plant. These eggs overwinter and become the first generation of females, known as stem mothers, next season. This cycle is highly standardized and should not be assumed for every aphid encountered.

Plant Response and Damage

In general aphids are a problem on spinach because of contamination of leaves. Aphids tend to be more numerous in late-summer.

Biological Control

There are many beneficial predators and parasitoids that can help manage aphid populations. While the lady bird beetle is one of the most commonly used predators, it is generalistic and opportunistic. This means that it will eat any small, soft bodied insect that it encounters and so it does not specialize in feeding only upon aphids. Predators that do specialize are generally more efficient at hunting and feeding upon the specified prey. Also, the immature lady bird beetles consume more aphids than an adult beetle will, but when ordering the beetle as a control agent, adults are usually the only option. Green lacewing (larvae are known as "aphid lions") and certain syrphid fly larvae are much better predators than the lady bird beetle is. There are specific wasps that parasitize aphids. To parasitize an animal, the wasp injects a single egg into the host, in this case the aphid. The aphid dies while the young wasp matures inside it, feeding upon the aphid's organs. When the wasp is ready to emerge as an adult, it chews or cuts a circular hole out the back of the aphids bloated and browned body.

Chemical control

Control should occur one week before harvest when used to avoid contaminaed foliage.

Due to constantly changing labels, laws and regulations, the sponsors of this web site assume no liability for the suggested use of any chemicals noted in the management section. Contact your local pest management personnel for current information on labeled pesticides that can be used for the intended plant disease, insect pest or weed.