Answer: Thank you for your question about rearing ladybugs. I have pasted an excerpt from the book, BENEFICIAL INSECTS - HOW TO MASS-REAR FOR A PROFIT because is addresses your question rather well. As this excerpt notes, most ladybugs sold commercially are collected, not reared.
Begin Excerpt: Is the above a misnomer? Perhaps, but a few people are trying to rear ladybugs. If their efforts prove successful, it will be a boon to the ladybug industry. Ladybugs sold today are from the wild where they cluster together by the thousands when the weather turns cold. They're brought in and sold to the public. Most of the time this is done in a slipshod manner.
Wild ladybugs are often infected with parasites - up to 20% of them. Also when they're sold without being pre-conditioned the ladybugs fly away from the release area and the customer has spent his money for nothing. This procedure doesn't bode well for good business relations.
Those growers who try to do better pre-condition the ladybugs with food and also weed out the parasitized ladybugs. Then the handler has a reasonably healthy crop to sell to the customer. Pre-conditioning helps satisfy the ladybug's instinct to fly away upon release. Even with a heavy aphid population at hand, a recently released ladybug taken from the wild will fly away.
Pre-conditioning entails surrounding the captured ladybugs with a large tent-like structure and feeding them well. The food is usually wheast or other preparations. Both of these activities satisfy the ladybug's tendency to fly away and keep them in good health where they are ready to lay their eggs as soon as the customer applies them to his crops. Unless you get your ladybugs already pre-conditioned, this should be the procedure you should use if you also deal in ladybugs.
ARE THEY WORTH ANYTHING?
The value of ladybugs to the customer is that each adult will consume as much as 5,000 aphids! They are indeed voracious eaters and have a variety of pest insects upon which they will feed. These include the Colorado potato beetle larvae as well as may kinds of aphids and thrips.
Ladybug larvae which look like little alligators with orange spots have an appetite just as great as the adult's. A ladybug larva will consume 50 or more aphids a day.
Ladybugs will lay up to 50 eggs per day. If conditions are good, the ladybug will lay a total of up to 1500 eggs. The eggs are laid on the bottom side of plant leaves. Within 2 to 5 days the larvae will hatch out and live for three weeks. At the end of that time they will pupate. It then takes about 4 days for them to emerge as adults.
The ideal temperature for ladybugs is between 62 and 80 degrees. If the temperature goes lower than 55 degrees ladybugs will slow down and not fly. They can be kept in storage for up to three weeks at a temperature of 40 degrees Fahrenheit. The relative humidity should be around 70 per cent.
IS IT POSSIBLE TO REAR THEM?
Perhaps. Here is a suggested way of going about it. If you try this method do so on a limited scale. Make sure it works before going whole hog at it. One producer has been raising ladybugs on Angoumois grain moth eggs for well over a year. To do this you would have to construct an open type setup. You would first make an enclosure which would keep the ladybugs and their larvae inside. This enclosure could be some sort of netting with holes too small for either the adult or the larvae to get through. The enclosure should be large enough to allow the adults to fly around inside.
You would have to have a means of feeding them. Sheets of waterproofed paper with smears of wheast could be hanging about. Also cotton balls which have been wetted down with water should be hanging here and there. Also there should be selected areas where the larvae might get a drink. Overall even this strategy would be difficult to maintain. How to collect them or their eggs? Difficult under this plan.
You can't keep them cooped up like you do with lacewing or Trichogramma. Ladybugs must have room to fly. Perhaps you can come up with a practical scheme. I don't see any problems with the feeding part of it; you could supplement with meal worms which you can raise yourself.
THE MAIN PROBLEMS WOULD BE SETUP AND SANITATION:
It would be difficult to sterilize a setup as outlined above. If you get your ladybugs from a supplier, be sure to get those which have been pre-conditioned and which don't have parasites. Be on guard for parasites anyway and get rid of them immediately if you find any. Remember: a satisfactory and sterile setup is mandatory. As an aside, a parasitized ladybug is immobile. It's alive but cannot move. The parasite is inside.
Since ladybugs are sold to the customer as adults, you would have to have a way to collect them. Perhaps by temporarily lowering the temperature to that listed above you could immobilize them to where they could be collected and sold.
But let's face it. This is all conjecture. The results of that one producer who says he's rearing ladybugs are not known. Ladybugs at present are still taken from the wild. Sometimes they're pre-conditioned and de-parasitized.
In the final analysis, this is something a producer would do when curiosity got the best of him. End of Excerpt.
Ladybugs live approximately one year. They hatch during April and May and immediately start to eat insects. The larva grow to about half an inch in length and look like small alligators, dark gray in color, with orange spots. After they reach full size, they go into a molting condition, clinging to weeds, grass stems, bark and leaves. After a few days their backs slit open and adult ladybugs emerge. Hippodamia convergens is the most common variety of ladybug. It grows to about 3/10" long, and is reddish brown with 13 black spots and two oblique white stripes just in back of the head.
Purchased Ladybugs: Release Instructions
Ladybugs will become dormant at low temperatures and may at first appear dead. As they warm up they become active. They will require water after their long dormancy, so sprinkle or irrigate gently before releasing them. If your ladybugs have been in storage for a long time, it is very helpful to feed them prior to release. Your local nursery may carry feed for ladybugs; a mixture of honey and bee pollen can also be used. Apply the food source to the screening of the ladybug case so they can feed on it prior to release. Ladybugs received during March, April, and May will be nearing the end of their life cycle and should not be refrigerated for long. If possible, release them the evening of the day they arrive. Do not release ladybugs during the heat of the day or while the sun is shining. Refrigerate them until it is nearly completely dark. If you do this, you will find them busily ridding your garden of pests the day after they are received. To prevent ladybugs from flying away, some growers spray a mixture of equal parts water and carbonated soft drink on their ladybugs immediately before releasing them. This sticky mixture glues their wings together for a day or two, discouraging them from flying away. For best results, place a few ladybugs around flowers, shrubs, and trees each day and keep the remaining ladybugs in the refrigerator. Do not allow ladybugs to freeze. In large fields, scatter the ladybugs in a central area and in spots where pest infestations are greatest. Ladybugs may be used successfully indoors, but must be released at night to prevent them from flying away. It may be desirable to screen the entrances to greenhouses or indoor areas to prevent the ladybugs from flying away before they have laid more eggs. Female ladybugs require a nectar and pollen source in order to mature and lay eggs. It is very important to have plant diversity, including a mixture of flowering plants, to provide this. If natural nectars and pollens are not available in sufficient quantities, provide an alternate source of food, such as those available at nurseries.
You will receive an average of 70,000 ladybugs per gallon, or 18,000 per quart. Generally, one quart of ladybugs will suffice for a large garden, but you may want to use more if pest density is high. Use one gallon for up to three acres. In orchards, use one gallon per acre. Grain crops may require as little as one gallon for every 10 acres. For melons and cucumbers, use one gallon for every 15 acres. For artichokes, use about 1 gallon for 10 acres. For alfalfa, a gallon for 10 acres around the time of the last frost is normally enough for the first release; after each cutting, a gallon for 15 acres is usually sufficient. For aphid control in corn, use one gallon for 10 acres.
Saffell, H.L. 2009. Rearing Ladybugs? http://www.mayhillpress.com/ladybug.html
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