At the recent Northeast Greenhouse Conference and Expo, the “Advanced Biocontrol Panel” with Suzanne Wainwright-Evans, Buglady Consulting; Ron Valentin, Bioline Agrosciences and Jeff Marstaller, Cozy Acres Greenhouses, there were many excellent questions.
What about using wild collected lady beetles (a. k. a., ladybirds or ladybugs) for aphid control?
When starting out using biocontrol agents, many growers consider using the well- known and familiar "ladybug" for aphid control. These generalist predators can feed upon aphids, soft scale, small caterpillars, and other small insects, as well as pollen and nectar. Ladybird beetles are relatively inexpensive to purchase and can be stored in the refrigerator. Wild collected ladybeetles are collected from the mountainous areas of the west coast where the lady bird beetles migrate and aggregate in large masses. This removes lady beetles from their native habitat. Because they are field collected and not mass produced, quality control guidelines for Hippodamia convergens have not yet been developed.
Adult beetles are highly dispersive and once released in greenhouses or high tunnels, most will leave, providing little or no control. They are also poor at searching out pests so need to be used when there are high populations of aphids. If wild harvested from natural winter aggregation sites, they may inadvertently carry natural enemies including endoparasites and pathogens that are easily overlooked and can potentially affect native ladybird beetles. Wild collected ladybird beetles may have been parasitized by a small wasp (Dinocampus coccinellae) that develops as an internal parasite and microorganisms including the microsporidium, Nosema hippodamiae that has been detected in some shipments. There is the possibility that these may affect native lady bird beetles. There is a need for a cost-effective rearing system for ladybird beetles for use against aphids, since the cost of producing them is high.
There are other species of ladybird beetles that are mass reared in commercial insectaries including: Delphastus pusillus (catalinae) (whitefly predator) Cryptolaemus montrouzieri (a mealybug predator) and Stethorus punctillum (a spider mite predator).
For more information:
Buying Ladybugs, Why Mother Nature Wouldn't Approve by Suzanne Wainwright-Evans, from Buglady Consulting, http://www.bugladyconsulting.com/
Webpages from Biological Control: A guide to Natural Enemies in North America website:
- Hippodamia convergens https://biocontrol.entomology.cornell.edu/predators/Hippodamia.php
- Stethorus punctillum https://biocontrol.entomology.cornell.edu/predators/spunctillum.php
- Cryptolaemus montrouzieri https://biocontrol.entomology.cornell.edu/predators/Cryptolaemus.php
Bjornson, S. 2007. Natural Enemies of the convergent lady beetle, Hippodamia convergens, Geurin-Meneville: Their inadvertent importation and potential significance for augmentative biological control. Biological Control.
October 2007 http://www.sciencedirect.com/science/article/pii/S1049964407002344
Unbiased, detailed information on using biological control is available in the 2017-2018 New England Greenhouse Floriculture Guide. The Guide is updated every two years by floriculture faculty and staff from the six New England State Universities, and is published by New England Floriculture, Inc. The 2017-18 edition of the Guide is available for $40 per copy via the Northeast Greenhouse Conference website (www.negreenhouse.org), and from the Extension publication offices of the University of Connecticut and University of Massachusetts.
Tina Smith, UMass Extension and Leanne Pundt, UConn Extension