About Lesson
Major Predators in Biological Control
Trichogramma spp. (Parasitoid Wasps)
- Family: Trichogrammatidae
- Hosts: Trichogramma spp. are egg parasitoids, primarily targeting lepidopteran pests like cotton bollworm, codling moth, and European corn borer.
- Biological Control: Trichogramma wasps have been successfully used for over a century to control lepidopteran pests across a variety of crops, including cotton, sugarcane, vegetables, and orchards. They are the most studied parasitoids globally and are mass-produced for field release in over 30 countries.
- Identification: Trichogramma wasps are small and often difficult to differentiate by appearance. Males are usually examined for accurate species identification.
Chelonus blackburni (Parasitoid Wasp)
- Family: Braconidae, Subfamily Cheloninae
- Hosts: Egg-larval parasitoid of pests like potato tuber moth, cotton bollworm, and various lepidopteran species.
- Biological Control: Used in integrated pest management (IPM) programs, particularly in cotton and potato crops. Mass production is commonly done on hosts like Corcyra cephalonica and Phthorimaea operculella.
- Field Application: Release dosages are typically about 50,000 adults per hectare or per release, depending on pest infestation.
Cotesia (Apanteles) spp. (Parasitoid Wasps)
- Family: Braconidae
- Hosts: Parasitoids of caterpillar pests, such as sweetpotato leafminer and various Noctuidae.
- Biological Control: Effective against sweetpotato leafminer and other pests, particularly in Hawaii. These parasitoids are considered significant mortality factors for pest populations.
- Mass Production: Cotesia species are bred on pest larvae and are then released in the field to suppress target pests.
Bracon spp. (Parasitoid Wasps)
- Family: Braconidae
- Hosts: Hosts include lepidopteran larvae, beetles, flies, and other insects.
- Biological Control: Bracon species are widely used in biological control due to their broad host range. They are ectoparasitoids, injecting eggs into host larvae and stopping their development.
- Field Application: Bracon wasps can be released in various agricultural settings to target pests like the tomato hornworm, cabbage worms, and various beetles.
Goniozus nephantidis (Parasitoid Wasp)
- Family: Bethylidae
- Hosts: Ectoparasitoid of the coconut black-headed caterpillar (Opisina arenosella).
- Biological Control: This parasitoid is host-specific to the coconut pest, and its use is crucial in managing the coconut pest populations in tropical regions.
- Field Application: Releases are typically recommended early in the season and include a mix of other parasitoids like Elasmus nephantidis for effective control.
Campoletis chloridae (Parasitoid Wasp)
- Family: Ichneumonidae
- Hosts: Larval parasitoid of pests like Helicoverpa armigera and Spodoptera litura.
- Biological Control: A key parasitoid for managing early instar larvae of Helicoverpa armigera in crops like cotton. However, its field application is limited by challenges in mass production and sex ratio imbalance.
- Field Application: Releases are done at a rate of 15,000 adults per hectare, with one to three releases depending on pest population density.
Major Predators in Detail:
Chrysoperla sp. (Common Green Lacewing)
- Family: Chrysopidae
- Predatory Behavior: The larvae of Chrysoperla carnea are active predators, feeding on aphids, mealybugs, spider mites, leafhopper nymphs, caterpillar eggs, scales, thrips, and whiteflies. The adults feed on nectar, pollen, and aphid honeydew but do not prey on insects.
- Biological Control: Chrysoperla carnea is used in biological control of pest insects, particularly in gardens and greenhouses. Eggs are released at a rate of about 1,000 eggs per 200 sq. ft. or 10 to 50 thousand per acre.
- Life Cycle: The larvae feed for 1-3 weeks before becoming adults. The adult insects consume only nectar, pollen, and honeydew to reproduce.
- Releases: Multiple releases may be necessary if the infestation persists 5-7 days after larvae have emerged. Available year-round.
Australian Ladybird Beetle (Cryptolaemus montrouzieri)
- Biological Control Agent: Known for controlling mealybugs and other scale insects, it has been introduced globally for this purpose, including in California, New Zealand, and Western Australia.
- Host Preferences: This ladybird feeds on mealybugs (family Pseudococcidae), soft scales (Coccidae), and felted scales (Eriococcidae), particularly the Australian golden mealybug. It has also been observed feeding on aphids.
- Economic Importance: C. montrouzieri is crucial for controlling mealybug populations, particularly in citrus and grape crops. It may leave once prey becomes scarce, requiring additional releases if mealybug populations rebound.
- Morphology: Adult female is 3-5 mm long, with red-brown thorax, legs, and head, and black shiny elytra. The larvae are 7-10 mm, covered in white waxy strands resembling mealybugs.
- Life History: Larvae and adults feed on mealybug eggs and other stages of mealybugs and other coccids. Development takes about 4 weeks at 27°C. The predator can lay several hundred eggs, with the total development threshold at around 0°C. Adults may live for months, feeding on honeydew.
- Temperature Sensitivity: Sensitive to low temperatures, which impacted its establishment in areas like North America and the Middle East.
