Native to North America, the zoophytophagous species, Dicyphus hesperus (Hemiptera: Miridae), is an invaluable tool in integrated pest management (IPM) as a beneficial insect. Feeding both on animals and plants, it has a particular appetite for whiteflies, including the Greenhouse whitefly (Trialeurodes vaporariorum) and Tobacco whitefly (Bemisia tabaci). While it also preys on two-spotted spider mites (Tetranychus urticae), thrips, aphids, and moth eggs, its role in pest control is more than just predation.
"Surfers" on sticky plants: trichome adaptation
One of the most remarkable traits of D. Hesperus is its ability to navigate glandular trichomes—sticky, hair-like structures found on plants like tomatoes that typically trap insects. "Unlike many predators that struggle with these sticky surfaces, D. hesperus has developed a unique ability to 'surf' across them," explains Dr. Omid Joharchi of Anatis Bioprotection. "Its legs and body are adapted to avoid getting trapped, allowing it to move freely and reach prey that other predators cannot."
Tracking prey through chemical cues
D. hesperus is a highly sensitive predator that uses volatile organic compounds (VOCs) emitted by plants under attack to locate its prey. "Plants release specific chemical distress signals when whiteflies and other pests feed on them," says Dr. Joharchi. "D. hesperus can detect these VOCs and home in on areas of high pest activity. In a way, it acts as a 'pest whisperer,' following the plant's own communication system to track its prey."
Using honeydew as a food source
D. hesperus also can utilize honeydew, the sugary excretion produced by pests like aphids and whiteflies. "While its primary role is predation, D. hesperus can consume honeydew when prey is scarce," Dr. Joharchi explains. "This behavior ensures its survival during periods of low pest populations. It almost functions like a 'farmer' by managing pest numbers just enough to maintain a steady food supply without eliminating them."
Egg cannibalism for survival
D. hesperus exhibits another unusual survival strategy in challenging conditions: egg cannibalism. "Adult females may consume their own or others' eggs to regain essential nutrients," Dr. Joharchi notes. "This occurs particularly when prey is scarce or environmental conditions are harsh. Beyond being a survival mechanism, this behavior helps regulate population density, preventing overpopulation and excessive resource competition."
A bioindicator of plant health
"Observing the activity of D. hesperus in greenhouses can provide valuable insights for growers," says Dr. Joharchi. "When plants experience stress due to pests or disease, D. hesperus becomes more active in its search for prey. This means that monitoring their behavior can offer early warnings of potential plant health issues."
Effective distribution and integration strategies
For optimal control of whiteflies and other pests, D. hesperus should be introduced at rates of 0.5-2 per square meter per week, with establishment taking at least six weeks. "When whitefly populations are low, supplementing with alternative food sources, such as frozen moth eggs (Ephestia kuehniella), can enhance establishment," Dr. Joharchi advises.
D. hesperus also works well in combination with other biological control agents. "Pairing it with parasitic wasps like Encarsia formosa and Eretmocerus eremicus improves whitefly management," explains Dr. Joharchi. "Additionally, banker plants such as mullein (Verbascum thapsus) provide a habitat where D. hesperus can feed and reproduce. For severe infestations, releasing groups of 100 adults in targeted areas and providing a steady supply of frozen moth eggs can be highly effective."
Using versatility to your advantage
The lesser-known aspects of D. hesperus highlight its versatility and importance beyond simple pest control. "Its ability to adapt to different food sources, navigate complex environments, and engage in sophisticated survival strategies makes it an essential component of modern integrated pest management systems," concludes Dr. Joharchi. "By understanding these unique traits, growers can harness the full potential of D. hesperus to maintain healthy crops while reducing reliance on chemical pesticides."
References for scientific information:
Gillespie, D. R., and McGregor, R. R. (2000). The Functions and Impact of Zoophytophagous Predators in Biological Control: A Review." Proceedings of the International Organization for Biological and Integrated Control of Noxious Animals and Plants, 23(1), 153-159.
McGregor, R. R., and Gillespie, D. R. (2005). Development and Survival of the Zoophytophagous Predator Dicyphus hesperus on Different Host Plant Species. Biocontrol Science and Technology, 15(7), 721-733.
Brodeur, J., and Cloutier, C. (2002). Impact of Glandular Trichomes on Herbivores and Predators: A Review. Environmental Entomology, 31(5), 1196-1208.
Dicke, M., and Baldwin, I. T. (2010). The Evolutionary Context for Herbivore-Induced Plant Volatiles: Beyond the 'Cry for Help'. Trends in Plant Science, 15(3), 167-175.
Hogervorst, P. A. M., Wäckers, F. L., and Romeis, J. (2007). Honeydew as a Food Source for Dicyphus hesperus: Its Effect on Survival, Development, and Egg Laying. Entomologia Experimentalis et Applicata, 124(3), 191-200.
Montserrat, M., and Bas, C. (2013). Cannibalism Among Eggs of the Zoophytophagous Predator Dicyphus tamaninii and Its Relationship with Food Availability. Journal of Insect Behavior, 26(4), 511-525.
Gillespie, D. R., and Quiring, D. T. (2007). Predator Activity as an Indicator of Pest Problems in Greenhouse Crops. Biocontrol Science and Technology, 17(3), 229-238.
Gillespie, D. R., and Raworth, D. A. (2004). Biological Control of Whitefly on Greenhouse Tomatoes Using the Predator Dicyphus hesperus. Biocontrol Science and Technology, 14(5), 465-471.
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