Green Lacewing Technical Bulletin

Green lacewings are proven broad-spectrum biological control agents, devouring eggs and young larvae of Colorado potato beetles, flea beetles, most caterpillar (worm) pests (armyworms, budworms, bollworms, borers, corn earworms, cabbage loopers, codling moths, etc.), aphids, spider mites, scales, psyllids, mealybugs, whiteflies, thrips, leafhoppers and other pests. Adult green lacewings have light green bodies, golden eyes and lacy wings. Lacewing adults live longer and lay more eggs when provided nectar, pollen and insect honeydews. Eggs are laid in foliage on the tips of silk stalks. The grayish-brown larvae resemble miniature alligators, and are 3/8 inch long when full-grown. Larvae search out pests, and use their pincer-like jaws to seize, inject digestive enzymes, and suck juices out of pests. During 2-3 weeks of life, one lone lacewing larva can consume 250 leafhopper nymphs in grapes (4th-5th instar), 300-400 aphids, 11,200 spider mites, 3,780 coccid scale crawlers or 6,500 scale eggs on pine trees. Interfering ants, waxy coatings or hard shells on pests and low temperatures deter lacewings from dining on and destroying pests.

Lacewing Pupae in Hexcel Units offer an opportunity to seed areas with lacewing adults, and enjoy the 300 to 1,100 eggs (depending upon species) each mated female can deposit in hard-to-reach areas. Lacewing pupae resemble tiny white or green balls, and are shipped in hexcel units of 500. Open containers and release adults daily for several days as they emerge. There is a two week delay until the appearance of pest eating larvae.

Adult Lacewings Adults are shipped in lots of 250-275 pre-fed females ready to lay eggs. Each unit has the potential to lay about 75,000 (C. carnea). Artificial diet may be needed to target adult egg laying and keep C. carnea in fields.

Farming with Green Lacewings

Lacewing Eggs on Cards

Applying Lacewing Eggs to Trees and Vines

Biological Control in Vegetable Crops

Biological Control Solutions for Cotton Pests

Biological Control Solutions for Pecan Pests

Biological Control in Greenhouses and Nurseries

Ant Management Products

"Hold" Predatory Insect Attractant

As a versatile general predator green lacewing consume many soft-bodied insects and mites and their eggs. They are the most economical commercially available general predator for many different pest situations. For use on a particular pest, if you have few pests present on your plants, lacewing will eat other insects and be available for pest flare-ups.

Notes on Release of Hatching Lacewing Eggs from Plastic Squeeze Bottles

Cartons of lacewing eggs (50,000 to 200,000 per carton) are usually mixed "with food" (frozen moth egg diet) unless customer wants "straight eggs--no food". Cartons can be marked by collection date as well as species if requested. Older eggs may hatch a little faster. Cartons are packed in cardboard box and shipped second day service if customer wants eggs developing in transit, or in an ice chest with warm or cold packs and shipped by overnight service if weather is extremely cold or hot. Open cardboard or foam box same day to let air circulate around the cartons. Inspect at least a random sample of cartons to become familiar with appearance of eggs before and during incubation period.

Timing of hatch is 2-5 days, but hard to predict unless temperature is controlled. We start incubating on arrival at 85º F; relative humidity should be above 35% RH if possible. Do not refrigerate eggs unless they were shipped very cold. You can hold them cooler, down to 60’ F to slow them down. You can manage the holding temperature of different cartons to stagger the hatch by 12-24 hours if desired.

Plastic squeeze bottles can be used to distribute hatching larvae along with predatory mites if desired for simultaneous release. A pint-size bottle can hold 1,000 mites and 5,000 - 10,000 lacewing per bottle for roughly 1/2 to 1 acre. Mixing When lacewing are between 25-50% hatching, mix the desired per-acre release amount gently in a cement mixer and fill the bottles using a funnel. Spoon roughly 1 ml hatching eggs or 2 mI if food was added (1/8-1/4 tsp or 5,000 eggs) per 250 ml corn grit or bran (2 cups or enough for one bottle). For 80 bottles of 5,000 eggs per bottle, mix 80 ml of hatching eggs (400,000 eggs) gently in 10 gallons of grit or bran. Corn cob grit can be ordered from Milihorn Chemical and Supply, Maywood, CA, TEL: 213-771-8301.

Calibrating bottles: Tips of bottles usually need to be trimmed slightly with a sharp knife so that grit or bran flows easily. Depending on the size of the opening, pint bottles hold approximately 300-500 puffs per bottle. Therefore, if you have 500 vines per acre, you would do 1 small puff per vine to finish a bottle 5,000 on one acre of edges and 1 puff per every 3-5 vines for the middles. It better to walk every other row releasing some in every row.

Releasing: Once they are mixed with corn grit, they must be released in the next 4 hours as corn grit can be desiccating. Time factor is probably not so critical with bran. Release in cooler parts of the day. Evening is good to give larvae overnight to find protection, but early is also good if there is dew, mist or water on the leaves.

To make pre-hatched larvae easier to release in trees and vines, you can cut narrow strips of hexcel (or verticel) honeycomb easy to cut into any size for spot releases. Just cut the hexcel into about 1 inch strips, peel off the organdy net cover, snip the strip into the size units for each release spot, and hang the units with twist ties or rubber bands.

Larvae will walk out of the paper honeycomb, out-running other predators better than larvae just out of the egg. They disperse through the tree or vine, voracious in their search of insects, mites and their eggs. Lacewing then pupate under leaves. The adults will continue to inhabit the farm or landscape that provides the pollen or nectar that the adults need to lay eggs.

Reasons why pre-hatched and pre-fed larvae are the best form of green lacewing for pest hot spots:

• unlike adult predators, they cannot fly away

• they can walk as far as 7 miles looking for pests and pest eggs

• unlike larvae just out of the egg, pre-hatched larvae are big and strong enough to live a few days and walk a mile or more to find food (depending on the temperature)

• unlike putting out lacewing eggs, the pre-hatched larvae are more able to fend off other predators and survive bad weather

• pre-hatched larvae are hungrier and eat more pests in one area without resting or moving on.

Lacewing eggs are placed into hexcel units - paper honeycombs - like a 3/8 thick slice of cardboard. Organdy material covers both sides. Food (non-viable Sitotroga grain moth eggs).

They are available with 175, 300 and the standard 650 larvae per hexcel.

The hexcels can be cut into smaller pieces for distribution. Use razor blade or sharp utility knife to cut the hexcel into small pieces. A 1.25 inch square contains about 20 larvae. Place the pieces into a paper bag or other container to carry into the field. Once in the filed next to a plant, pull the organdy material from one side of the hexcel. Use a rubber band or twist tie to attach the hexcel to a plant.

Another way to release them is to walk to an infested plant, pull the organdy back a short distance to expose a few cells, turn the hexcel upside down and tap the larvae out. Or use a small brush to flick one lacewing at a time onto a plant.

To hold for later release: If you think you will need to hold the larvae for more than a day, you can order frozen sitotroga eggs to feed them (when you order the lacewing larvae). Place the hexcel unit on a flat surface. Sprinkle the eggs on top of the organdy material on the hexcel. The larvae will reach through the material to feed on the eggs. Once a day tap off the eggs onto a piece of paper and sprinkle then back onto the top (to redistribute the eggs). Do not refrigerate. Refrigeration at this stage could damage the developing larvae.

Ants will fight off lacewing larvae from aphids they are protecting. Ants generally interfere with biological control, and in particular they will attack and drive lacewing larvae away from aphids, whitefly, mealybug, and soft scale. These honeydew secreting pests supply sweets to the ants. Put attention to controlling ants. The simplest thing you can do is to stick a shovel into ant mounds and disrupt the colony.

Hot Spots: Pest outbreaks often occur in "hot spots" or edges of orchards or landscapes. Heat or dust from a road, exposure to nearby infested plants, or drying winds may shift the ecological balance of predator and prey in your plantings. Treating the hot spot or edge often is all that is needed to control the outbreak. The extent, situation, and location of the infested area will determine the best application method for your needs.

Lacewing Release Guidelines: Effective programs range from two to four releases seven to fourteen days apart. Use 660 to 5,000 prefed larvae per acre or 100 trees.

Ideally, releases of beneficials are started as early in the season as possible, when the first pests enter your fields or neighboring crops. One of our most popular strategies is initially releasing small numbers of beneficials to colonize young plants, and following up with a series of weekly releases to insure long-term establishment of pest-destroying natural enemies. Farming ecologically with biological control inputs gets easier each year, as a reservoir of natural enemies becomes established. The insect ecology of each farm and season is unique, but some general guidelines are available from research.

Green lacewings go after aphids on vegetables first, but also attack thrips, spider mites, whiteflies, moth eggs, young caterpillars and other pests as aphids are cleaned up. Numbers of lacewings needed depend upon many factors, including pest numbers, temperature, other natural enemies, etc.

Studies in Finland using Chrysoperla carnea against bean and green peach aphids on parsley achieved control with a predator:pest ratio of 1:27 (230 eggs/m2). On green pepper a higher ratio of predators was needed, whereas on greenhouse asparagus, 40 eggs/m2 controlled green peach aphid for three months. "During the spring-summer period, the initial ratio of predator to prey should be 1:15 on most fast-growing crops, but 1:50 on celery and dill, and during the autumn-winter period it should be 1:10 on spinach beet, 1:25 on celery and 1:30 on lettuce." Fall cabbages with waxy aphids require 1:1 for 74% control, and 1:25-50 for 50% control.

In USDA studies (Nordlund), lacewing larvae placed on potato plants when Colorado potato beetle (CPB) eggs begin hatching prevents damage (potatoes without lacewings are defoliated). Buckthorn aphid on potato was reduced up to 96% and green peach aphid 83% with 34,000 lacewing per acre; potato aphids were not affected. In the Ukraine, 2-3 releases of C. carnea (50-60,000 per year) at 10-15 day intervals were 85-96% effective against CPB on potato. On eggplant, similar numbers of C. carnea larvae released 3-4 times at 7-10 day intervals at a 1:20 predator:pest ratio were effective. Other pests, such as thrips, are also stopped on potato, eggplant, tomato, and pepper.

Releasing lacewing in borders of early crops (e.g. wheat, barley, sorghum, corn, sunflower, alfalfa, oilseed Brassicas) results in large early season movement into later plantings of vegetables, soybeans, cotton etc. For example, lacewing releases in forage sorghum interplanted with cabbage increased lacewing eggs on cabbage 1,000%. Sunflower or corn borders planted 60 and 30 days ahead of tomatoes and inoculated with beneficials protect the tomatoes. Early inoculation yields more natural enemies than can be purchased to hold down whiteflies, fruitworms and other pests.

Adjacent unsprayed grain and oilseed fields can supply 4-12 predators per cotton plant (predator:pest ratio of 1:65-73), completely control aphids, and then reduce moth eggs from 600 per 100 plants to where only 5 worms (caterpillars) survive per 100 plants. In a Soviet experiment, eggs and early instar C. carnea larvae were released three times at a 1:1 predator:pest ratio. A week after the first release, there were 98.5% fewer aphids, 95.6% fewer thrips, 100% less bollworm eggs and 50% fewer young bollworms. In fields without lacewing releases, aphid abundance increased 180%, thrips 160%, spider mites 240%, bollworm eggs 150%, and young bollworms 230%.

Green lacewings destroy pear psylla, thrips, spider mites, aphids, mealybugs, scale crawlers and eggs of caterpillars like the notorious codling moth in apples and pears. They are recommended for landscape trees by the Texas Department of Agriculture and used by parks and municipalities for street trees. In Indiana, green lacewings destroyed 20% of codling moth eggs on apples, something to consider with Rincon-Vitova's Trichogramma from codling moth. In Poland and China, releasing 1 first instar lacewing larva per 10-25 leaves greatly reduced and kept European red mite populations on apples very low. In a definitive 1940s U.S. study, 3 well-timed spring and summer releases of 250 C. carnea eggs in crowns of pear trees (27,000 eggs/acre each release) in alternate years controlled grape mealybug.

Green lacewings combat most vineyard pests, including leafhoppers. Best results are obtained by closely monitoring vineyards, and timing lacewing releases to coincide with emergence of each new pest generation, beginning in spring.

Green lacewing larvae are very effective in dense foliage where pests are evenly distributed, and on low growing plants. In Kansas, releasing an average of 1 green lacewing larvae per snapdragon plant per week during 8 weeks controlled green peach aphid. Aphid control is a week faster at 75º F than at 70º F. Screens and artificial light extending total light to 12-14 hours may enhance winter reproduction. Sugar-yeast feeding stations show promise for keeping lacewings from disappearing from greenhouses, but periodic releases every 2-4 weeks are still recommended. The aphid midge, Aphidoletes aphidimyza, offers long-term, low-density aphid control after lacewings knock down high aphid populations.

Green lacewings are among the hundreds of beneficial predators commonly devouring agricultural pests along with brown lacewings, pirate bugs, big-eyed bugs, assassin bugs, damsel bugs, spined soldier beetles, lady beetles, Staphylinid rove beetles, Carabid ground beetles, Collops beetles, six-spotted thrips and mites (not to mention the parasitic wasps and flies). Slight changes in farming can nurture this natural enemy complex and avoid the pest flare-ups taken for granted under conventional chemical farming. Techniques of crop rotation, hedging, refuge management can make a difference. Strip cutting (harvesting alternate strips or fields of alfalfa or cover crops when they begin to bloom), for example, forces a steady migration of beneficials into nearby row crops yielding many times the natural enemies of uniformly cut hay fields or cover crops. Strip or trap cover crops that are never sprayed offer a field insectary and off-season refuge for increasing beneficial insects without harm to market products. Parasites live several times longer and destroy more pests when there are weeds or other plants to provide nectar. In California almonds and peaches, for example, lacewing eggs are 100 times more abundant with cover crops than without. Integrated management of predators and parasites is the key.

The elegant green lacewing is a general predator and will consume many soft bodied insects and their eggs, including mites and pest thrips. Lacewing is the most economical commercially available general predator for many different pest situations. Releasing lacewing eggs or hatching larvae in trees requires specialized packaging or equipment to keep them in the leaves.

Hot Spots: Pest outbreaks often occur in "hot spots" or edges of orchards or landscapes. Heat or dust from a road, exposure to nearby infested plants, or drying winds may shift the ecological balance of predator and prey in your plantings. Treating the hot spot or edge often is all that is needed to control the outbreak. The extent, situation, and location of the infested area will determine the best application method for your needs.

Lacewing Release Guidelines: Effective programs range from two to four releases seven to fourteen days apart at 1,000 or more eggs per 2,500 square feet or from 2,000 to 30,000 eggs per acre. With prefed larvae and adults, use 660 to 5,000 prefed larvae or 200 to 500 adults per acre or 100 trees.

Lacewing Conservation Tips: Minimum releases of larvae in borders of early blooming varieties of insectary refugia of grasses, corn, sunflower, legumes, oilseed Brassicas, or the California native perennials (Ceanothus, kurrajong bottletree, hollyleaf cherry and soapbark tree) results in large movements of adults into later varieties of trees, ornamentals and vegetables, Artificial pollen sprays and sticks also lure lacewing back into your plants.

Packaging Options: Lacewing eggs, larvae and adults are available in several forms for easy release in trees, shrubs, and vines. Eggs are available in bulk or glued to card stock. Larvae are available in honeycomb cardboard strips.

Lacewing Eggs on Cards: Eggs glued onto card stock which is perforated to separate into tabs or hangable units (purchased by the card of 30 perforated hangable units) have a loop on one end for hanging on a twig. Hangable units are hung on twigs in parts of the tree that have pest infestation (or are accessible). The hangable units can be protected during hatching by fixing a hangable unit inside a small paper cup which can be hung from a knotted string through the bottom of the cup. Cups or hangable units can also be stapled to leaves.

Lacewing Eggs in Carrier: If lower tree branches are accessible and the bark has a rough texture, eggs hatching in a carrier, such as rice hulls, can be sprinkled by spoon in the crotch of each tree. This has been a successful, inexpensive method used in large pecan orchards. Open or punctured "Ajax" wedge paper cups (used for water dispensers) can be used to hold small quantities of eggs while larvae are emerging. A Post-It-Note (3 X 3 inch) can be folded with the sticky strip around a twig to form a trough for the eggs.

Prefed Lacewing Larvae in Strips of Honeycomb Cardboard: To make pre-hatched larvae easier to release in trees and vines, Rincon-Vitova Insectaries, Inc. has developed narrow strips of honeycomb cardboard that are easy to cut into any size for spot releases. The larvae are raised in the cells covered with organdy net. Just cut the organdy between the strips, snip the strip into the cells wanted for each release spot, peel off the organdy net cover, and hang the units with tape or rubber bands.

Prehatched larvae will walk out of the cardboard honeycomb, out-running other predators better than larvae just out of the egg. They disperse through the tree or vine, voracious in their search of insects, mites and their eggs. Lacewing then pupate under leaves. The adults will continue to inhabit the farm or landscape that provides the pollen or nectar that the adults need to lay eggs.

Reasons why pre-hatched and pre-fed larvae are the best form of green lacewing for pest hot spots:

• unlike adult predators, they cannot fly away

• they can walk as far as 7 miles looking for pests and pest eggs

• unlike larvae just out of the egg, pre-hatched larvae are big and strong enough to live a few days and walk a mile or more to find food (depending on the temperature)

• unlike putting out lacewing eggs, the prehatched larvae are more able to fend off other predators and survive bad weather

• pre-hatched larvae are hungrier and eat more pests in one area without resting or moving on

Lacewing Adults: As a rule there is no better method for getting lacewing into tall trees than to release as adults. Adults will start laying eggs in five days. By planning releases early, the eggs laid by released adults are perfectly placed near prey suitable for the larvae. This is a popular program for aphid control in street trees where they can be colonized. To keep the adults in your area, providing flowering plants with nectar is essential. Check lists of beneficial insect attracting plants that grow in your area. Corn is an excellent source of nectar (from extrafloral nectaries) and protection for lacewing adults. Adults require special handling for shipping. Pupae in honeycomb cardboard units can be purchased which will emerge in a few days for release as adults (the pupal stage is about five days).

Aerial Lacewing Egg Release: Aerial releases of eggs and larvae by airplane and by remote control airplane have been used, the problem being that many fall to the ground. Some crop dusters have created equipment similar to pollen applicators with a venturi mechanism out of the airplane floor. Passes are made across field rows in the early morning. The preferred carrier for mass field releases may be rice hulls. In indoor plantings, tethered helium balloons have been used with a "toy" scoop carrying the lacewing eggs in a carrier such as vermiculite. A release lever for the scoop is controlled by a separate string.

Backpack Biocontrol Applicator Release: The Rincon-Vitova Backpack Biocontrol Applicator, produced by Maruyama Corporation, is a multipurpose machine for delivering dusts, granules and liquids, including cover crop seeds, fertilizers, biologicals and pesticides. Either dry or liquid products are dispensed from the same 3.4 gallon (12.9 liter) chemical tank with only minor modifications.

This backpack mister/duster has been modified, tested, and calibrated by Rincon-Vitova for delivering biocontrol agents such as lacewing eggs, Trichogramma pupae in sitotroga eggs, predatory mites, and beneficial nematodes. Biocontrol materials can be applied in swaths up to 20 feet wide while walking.

Specialized attachments and a sticker material are available to customize the Backpack Biocontrol Applicator for different application jobs, making this a very versatile tool.

Biosprayer Release: A spray rig with a PTO towed behind a tractor has been adapted for spraying on lacewing eggs. This can be used for releases on a massive scale.

Green Lacewing Introduction