Green Lace Wing (Chrysoperla carnea) ; A Biological Control Agent

Kingdom: Animalia

Phylum: Arthropoda

Class: Insecta

Order: Neuroptera

Family: Chrysopidae

Subfamily: Chrysopinae

Genus: Chrysoperla

Distribution and Habitat

C. carnea is considered a single Holarctic species scattered across North America, Europe, North Africa and Asia. This species is usually found in herbaceous vegetation in open fields during summer and in urban areas in fall and spring.

Morphology

Adult green lacewings are a pale green colour with long, threadlike antennae and glossy, golden, compound eyes. They have a delicate appearance and are from twelve to twenty millimetres long with large, membranous, pale green wings. Larvea are brown and are about one millimetre long when they first hatch. The larvae grow to about eight millimetres long before they spin circular cocoons and pupate. Eggs are oval and secured to the plant by long slender stalks. They are pale green when first laid but become gray later. The lower growth threshold of C. carnea is about 10 ˚C.

Life Cycle

The Chrysopa adults overwinter covered in leaf litter at the edge of fields or other bumpy places, emerging when the weather warms up in spring. Each female lacewing lays several hundred small eggs at the rate of two to five per day, choosing obscured spots underneath leaves or on shoots near latent prey. The eggs are normally laid during the hours of darkness.

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The larvae hatch in three to six days, eat avidly and moult three times as they grow. They feed not only on aphids but also on many other types of insects and even prey on larger creatures, such as caterpillars. When food is limited they turn cannibal and eat each other. After two to three weeks, the mature larvae secrete silk and build round, parchment-like cocoons in cloaked positions on plants. The development of the cocoon usually lasts for one or two weeks and depends on several factors, mainly temperature and sex. For example, cocoon development is completed in 7.1 days at 24°C and in 12.7 days at 20°C

From these, the adults emerge ten to fourteen days later. The length of the life cycle (under 4 weeks in summer conditions) is greatly inclined by the temperature and there may be several generations each year under positive conditions.

Uses

⦁ Classical biological control, by introduction of a new natural enemy

⦁ amplification by means of inoculative releases

⦁ intensification by means of inundative releases

⦁ Conservation

⦁ Effective biological control agent

Chrysoperla as biological control agent:

mass-rearing chrysoperla for use in biological

The mass-rearing of commercially available chrysoperla is mainly based on eggs of lepidopteran specie genera Sitotroga, Ephestia (Anagasta) and Corcyra that have been proved as nutritionally better and of low cost food to produce, in comparison to other artificial diets tested. For suppressing sucking pests, egg cards of C. carnea are used in different numbers like 50 cards for Sugarcane and vegetables and 25 for cotton. One card contains 20-25 eggs of C.carnea. Rearing of C. carnea in the glass cages proved superior than other types of cages, requiring minimum time from the point of sanitation, food provision, egg harvesting and handling of adults. This will save labour costs and will be more economical than other types of cages for mass production unit in an insectary.

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For C.carnea is ideal temperature is 22-27 degree Celsius. At high temperature insect become fidgety. Food is provided in 1:1:1 Yeast, Honey and mineral water with the help of moving plastic bars. Freshly laid eggs of S. cerealella after weighing to a specific quantity, placed in each vial larval diet. S. cereallela eggs are suggested as more competent and economic host as compared to P. solenopsis crawlers. Its life cycle is about 19-31 days. The green lacewing adults emerge from litter when the weather becomes warm during spring season. Female lays several hundred eggs with the ratio of two to five per day.

Eggs are normally laid during the darkness. The larvae hatch in three to six days. Then larvae secrete silk type fabric and form cocoons. Adults emerge 10 to 14 days later. Eggs are harvested from consumable black muslin cloth cover with the help of sharp razor blade. Eggs laid on other structures within cage such as cage walls, water containing vials etc. After collecting eggs on cards, the cards are supplied to the farmers.

Risks

⦁ The possibility of global or local extinction of a native species;

⦁ Large reductions in either the distribution or abundance of native organisms;

⦁ Interference in the efficacy of native natural enemies of pests via interactions or competitive displacement;

⦁ Vectoring of pathogens harmful to native organisms

⦁ Loss of biodiversity and identity of native

⦁ Species via hybridization between close relatives

⦁ Disperse and leave the target field before ovipositing

Characteristics

Larval characteristics:

⦁ Resistance to insecticides

⦁ Short developmental times:

⦁ Predation efficiency:

⦁ Low dispersal ability

⦁ Broad prey range

⦁ Effective biological control agents

Adult characteristics:

⦁ Easy mass – rearing

⦁ High reproductive potential

⦁ Attractions to protein hydrolysates

Shoaib Naeem, Jahangir Ahmad, Muhammad Asad, Muhammad Muddassir

University of Agriculture Faisalabad, Pakistan.

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