Beneficial Organisms for Landscapes and Gardens

Biological Urban Pest Management

City dwellers have been taught by insecticide advertising to hate or fear all insects. The public is learning to respect the importance of insects in nature. Household purchases of natural pest controls have increased by 400% since 1989. Families with children and people who have health problems or chemical sensitivity especially welcome this safe alternative to toxic chemicals.

Biocontrol Makes Dollars and Sense: Landscape maintenance is moving steadily in the direction of biological control, mainly because of the high cost of chemical pest control and public concern for the environment. Park and landscape managers report as much as 50-75% savings in pest control costs when they switch to biological programs.

Employee safety and liability concerns with sprays are another reason for landscapers to switch to biocontrol. Better plant vigor may be noted when pesticide stresses on plants are stopped. Biological control helps to conserve not just beneficial insects, but also less common birds, reptiles and mammals. City and suburban dwellers appreciate healthy, natural outdoor sights and sounds.

Managing Beneficials and Habitats: Not all plants get pests at the same time. There are often pest "hot spots" to target with larger numbers of beneficials or to spot-treat with least toxic materials. Broad-spectrum and systemic pesticides destroy the beneficial insect and mite species. Dust and ants can also interfere with beneficial organisms. Manage ants by destroying their pathways, pruning branches off the ground, using sticky barriers or least-toxic baits, and disrupting hills and runs with a shovel, flood of water or mulching which cause the ants to cannibalize their young while they rebuild the nest.

Rincon-Vitova Insectaries provides a variety of beneficial predators and parasites for pest management in landscapes and gardens.

Green Lacewings: Hardy Predators

Lacewings are among the most voracious and common general predators. They attack almost any soft-bodied insect and their eggs. They especially go after aphids, but also attack small worms, whiteflies, mealybugs, soft scale, leafhopper nymphs, spider mites and insect and mite eggs.

Two species of lacewing are available from Rincon-Vitova Insectaries. Chrysoperla carnea can be useful in field and low vegetation and where pesticide residues may be present, since it is a strain coming from field crops in California that have been heavily sprayed. Chrysoperla rufilabris from pecan trees in Georgia, tends to dominate in tree crops, but the larva are fine in any vegetation. In many diverse gardens and landscapes, a mixture of species may be best.

During a two to three week larval stage, one lone lacewing can kill 300-400 aphids, 11,000 spider mites, 3,700 scale crawlers or 6,000 scale eggs. Adults are not predatory, but with supplies of insect honeydew, floral nectaries or pollen, the adults will lay eggs near pests to feed the next generation.

Lacewing Release Guidelines: Effective programs range from two to four releases 7 to 14 days apart at 1,000 or more eggs per 2,500 square feet or from 2,000 to 30,000 eggs per acre or 660 to 5,000 pre-fed larvae or 200 to 500 adults per acre or 100 trees.

Lacewing Conservation Tips: Minimum releases of larvae in borders of early varieties of insectary refugia of grasses, corn, sunflower, legumes, oilseed Brassicas, or the California native perennials, such as 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 lacewings back to the garden.

Packaging Options for Lacewing: In addition to growing various species of lacewing, Rincon-Vitova customizes its packaging of green lacewing. Loose eggs are packaged in increments of 5,000 or 10,000 in bags or cups in rice hulls or vermiculite or no carrier. Loose eggs can be sprinkled or blown into dense foliage or spooned on tree limbs.

Cards: Rincon-Vitova offers packaging for lacewing eggs for vines and trees with sparse foliage. Eggs are glued in units of 5,000 on cards that are perforated into 30 hangable units averaging a minimum of 170 eggs per unit.

Pre-fed Larvae: Pre-fed larvae are ready to feed on larger prey and move greater distances in search of prey. The larvae are kept separate from each other in a cardboard verticel honeycomb unit with a minimum of 500 larvae. Organdy net is peeled off so larvae can be tapped or lifted onto foliage.

Lacewing adults are used for releasing in large trees. 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 along with Aphidoletes releases in settings where they will colonize (see below).

Ladybugs

The convergent lady beetles (Hippodamia convergens or the common commercial ladybugs) are very popular for urban pest management, however, during parts of the year when the beetles are relatively fresh from the mountain collection sites, they are likely to fly away upon release. The early spring inventory of lady beetles is often left over from the previous season's collections. Their fat stores have been depleted in storage and, though there may be a few dead ladybugs from longer storage, the beetles from storage are generally more likely to stay in the area, feed, and lay eggs.

Ladybugs are most useful, when available, on early aphids before it is warm enough to release green lacewings. Ladybugs can also knock aphids down during the season, especially if released in cool, cloudy weather. Once the new season's ladybug collections come on the market, it is often more cost-effective to buy green lacewing larvae since they will stay put and eat lots of prey before they pupate. One ladybug per square foot is the release guideline

Aphid Midges

An effective part of long-term aphid control in urban settings is to colonize the aphid midge Aphidoletes aphidimyza. This aphid predator overwinters in tree, perennial ornamental and rose garden settings where there is protection from wind. They will colonize even where it snows. Re-introduction may not be required for three or four years. Wait after use of systemics and insecticides which are very harmful to the midges and the naturally occurring aphid parasites. Water-soluble fertilizer and fungicides that fall on the soil will not be harmful to midge larvae.

Aphid Midge Release Recommendations: A minimum order of 250 cocoons is enough for most home gardens. Rose bushes should receive 3-5 midges per bush and apple and shade trees should receive 5-10 midges per tree in spring when aphids appear or in mid to late August to reduce overwintering aphid egg populations.

Orius insidiosus, Minute Pirate Bug, for Thrips

Orius is a predatory bug that feeds on many species of small, soft-bodied insects, especially Western flower thrips. All stages of Orius move very quickly. The adults are good flyers and move efficiently to locate prey. Orius are generalist predators that consume a variety of pests including mites, aphids, and small caterpillars. They are most effective for pests with life stages that inhabit flowers (such as flower thrips). Optimum conditions are temperatures over 59° F (15° C) with relative humidity over 60%. Typical greenhouse temperatures of 64-82° F (18-20° C) and humidity are suitable for Orius development. Orius are packaged 500 in a bottle with a carrier of buckwheat hulls. Sprinkle on plants to distribute, as soon as possible after they arrive.

Predatory Mites

A proven control for several pests, predatory mites are shipped as adults in a carrier or on bean leaves and should shipped by overnight service and released immediately. The best species for aggressiveness against two-spotted spider mite (TSSM) are Persimilis and Fallacis as long as conditions are not too hot or dry. Other species are available for a wider range of pests and climate. Here is more detail about the species that are sold:

Phytoseiulus persimilis Used in gardens, greenhouses and landscapes in mild conditions up to 80º F. Persimilis is available in units of 500, 1,000, 2,000 in a bran or vermiculite carrier and 1,500 on bean leaves. They can be combined in units of 1,000 with other species listed below. Mixtures, especially with Amblyseius californicus, increase the likelihood of the presence of predatory mites. Mixing Persimilis with Fallacis, Occidentalis or Longipes takes advantage of each mite’s differing habitat preferences within the plants and under changing weather. A recent study showed that releases of Persimilis and Californicus reduced the population of the pest T. cinnabarinis two weeks earlier than either mite released alone.

Galendromus occidentalis prefers hotter temperatures and pest mites that aggregate in webbed colonies and is available in units of 1,000 which can be mixed with P. longipes.

Amblyseius fallacis performs best below 70º F, overwinters and is resistant to Imidan and the miticides and all but one of the available fungicides except Benlate. Release after the first appearance of two-spotted spider mite, European red mite, spruce red mite and various other mites before the pest mite density reaches one per leaf. Very helpful for fall clean-up to effectively reduce overwintering pest mite populations.

Phytoseiulus longipes tolerates warmer and drier conditions and is often combined with A. californicus when conditions are too warm and/or dry for P. persimilis.

Amblyseius californicus forages better than other predators for the mites that do not aggregate at high densities.

Amblyseius cucumeris is a predator of immature stages of Western flower thrips and onion thrips and is available in packets of 1,000 predators or in smaller hanging sachets.

As for more detailed information on the life cycle and the kinds of programs where these predators can be used. It is important to apply before the two percent level of infestation at the rate of one-half to two predators per square foot. Control of heavy infestations of spider mites is difficult without first knocking pest mites down. Very leafy trees and planters may require 500 to 2,000 or more of the predatory mites per tree in weekly or biweekly releases to achieve a predator to pest ratio of one to 10 that will eventually clean up the infestation.

Rhyzobius lopanthe, Scale Destroying Beetles

Shipped as adults, the life cycle is 35 to 60 days and activity occurs at temperatures as low as 40ºF. A rate of about five beetles per square yard or three to five beetles per plant or 20 to 40 beetles per scale-infested tree are variously suggested.

"Crypts": Mealybug Destroyers

Two releases two weeks apart beginning in early spring at the first sign of mealybugs will set them up for the season. They only overwinter in the warmer coastal regions. Use a rate of one beetle per square foot of planting or two to five per plant.

Beneficial Nematodes

Beneficial parasitic nematodes are natural and legal and safe for controlling soil-born pests in the larval stage. The microscopic infective nematodes enter the larvae and release a bacteria that eventually kills the host. The nematodes feed on the bacteria and the decomposed host tissue where they reproduce until numbers drive them out to find a new host.

Nematodes are effective against over 250 species of pests. In field crops, they kill caterpillars, cutworms, grubs, rootworms, wire worms, flies and other pests. Orchard worm pests, like codling moth, can be attacked in the soil during the winter with nematodes. Lawn and turf pests, such as white grubs, billbugs and Japanese beetles are successfully destroyed with nematodes. Generally use Heterorhabditis bacteriophora (Hb) for grubs or beetle larvae. The more cold-hardy species is H. marelatus and the more heat-tolerant is H. indica. Steinernema carpocapse (Sc) is used for moth larvae, and Steinernema feltiae (Sf) for fly larvae.

Nematode Release Guidelines: One million nematodes covers an area of 50 to 500 square feet. One hundred million will cover 1/8 acre to one acre.

Decollate Snail, Predator of the Brown Garden Snail

Rumina decollata the predator snail, consumes brown garden snails in the immature stages, but not full-grown snails or slugs. They are released under irrigated perennials near moist organic matter. About 100 snails will colonize a yard or about 1,000 per acre of orchard. They overwinter and colonies can be moved around. They are not allowed for release outside of Southern California counties.

Trichogramma, Moth Egg Parasite

Trichogramma is an egg parasite of moth eggs that become caterpillar pests. The tiny wasp must be released when moths are laying eggs and the scheduling and cost of the program depends on the number of generations and other factors in the life cycle of the caterpillar pest. To save shipping costs for small amounts, overnight cold-packed shipments are held cold and released over two to three weeks. Lacewing releases are included to assure overlapping generations of predators.

Trichogramma platneri may be useful against oak and other worms in landscape and garden settings in Western states of the US. It helps to be able to anticipate the beginning of moth flight and egg laying for an effective program.

Trichogramma pretiosum or Trichogramma mniutum is released normally on a weekly basis against corn earworm, tomato fruitworm, hornworm, cabbage looper and cabbage worm and cutworm pests in large garden plantings. Trichogramma brassicae is available for cabbage looper

Trichogramma Release Guidelines: When releases are Trichogramma Release Guidelines: When releases are started early, releasing about 10,000 to 30,000 Trichogramma per week for 10 to 12 weeks will control low to moderate infestations. Covering each generation of the moth pest with regular releases of 12,000 to 50,000 Trichogramma per acre will achieve an acceptable minimum 80% egg parasitization level in landscape and garden settings.

Whitefly Parasites and Predators

Green lacewing is our first strategy against whitefly and Delphastus beetles should be colonized on early infestations. Encarsia and Eretmocerus wasps in a proactive regular release program can be used for specific kinds of whitefly. Have whitefly identified before planning parasite releases. Knock down high levels with insecticidal soap, vacuuming or sticky trapping.

Fly Parasites and Traps

Small wasps are present in nature along with predators and microorganisms to control houseflies. Rincon-Vitova's mixture of fly parasites are among those that are found in nature to attack several species of flies that breed in accumulations of decaying organic matter, such as manure, piles of grass clippings and edges of compost piles. The wasps lay their eggs inside fly pupae and emerge as young wasps ready to seek and destroy more flies.

Fly parasites complete a generation every two to four weeks for a steady increase in fly parasites over the warm summer months. Flies breed faster in hot wet conditions, so extra releases may be needed then. Wasps need to be released each spring at the first sign of flies and periodically during the fly season.

Fly Control Guidelines: A minimum order of 10,000 fly parasites treats a backyard, especially if fly-breeding areas are cleaned up and a trap is maintained for adult flies.

Rincon-Vitova Insectaries Guarantees Quality and Support: Our insectary has been the pioneering impetus for a growing biocontrol industry since the late 1950's. With hundreds of landscape managers and horticulturists in private business and at univer-sities, government and other research institutions, we have proven to be a reliable, supportive and quality supplier of beneficial organisms.