What is Biological Pest Control?
Biological pest control is the application of biocontrol organisms such as predators, parasitoids and pathogens to reduce pest population and possible disease as result of infestations on plants. Biological pest control is used as part of an integrated pest management (IPM) strategy. Below is a description of the most common biocontrol organisms specifically used in greenhouses, including their life cycles and additional details.
Biocontrol Organisms
Predators
Beetles
Cryptolaemus Montrouzieri (Mealybug Destroyer)
This type of ladybird beetle is from Australia. This is one of the most effective predators used for biocontrol for mealybugs including citrus mealybugs and all cottony egg mass producers. Every stage of mealybugs is consumed by both young larvae and adults. The adult beetle has a dark brown abdomen, orange-brown thorax and head and is four millimeters in length.
The life of the female is about two months. During this time, 10 eggs are laid per day in mealybug eggs or colonies. Larvae emerge when the eggs hatch, growing 13 millimeters in length. You can recognize the eggs by the waxlike white filaments. The white secretion is often confused with mealybugs. Young larvae voraciously prey on mealybugs in the early stages.
Mealybugs of all sizes are consumed by the larger larvae. Cryptolaemus is extremely active when the relative humidity level is between 70 and 80 percent, the temperature is a minimum of 72 degrees Fahrenheit and there is sunny weather. The day you release the beetles, keep your vents and windows closed due to their ability to fly.
Delphastus Pusillus (Whitefly Destroyer)
This ladybird beetle will destroy whiteflies. The delphastus is less than two millimeters in length, black and consumes whiteflies in every stage despite being partial to nymphs and eggs. As many as 12 large nymphs or 160 eggs are consumed daily. You can control every species of whitefly with this predator or combine them with parasitoid wasps.
A large supply of whiteflies is necessary to ensure delphastus beetles have enough food to reproduce. This is the reason you should release a minimum of 25 beetles close to every large whitefly population.
Hippodamia Convergens (General Insect Predator)
This general predator is a ladybird beetle effective for eliminating or controlling hot spots. These beetles feed on soft-bodied insects including thrips, scales and aphids. If they are in a dormant state when collected, they usually migrate before laying eggs or feeding. They can be fed a special diet for preconditioning to minimize their behavior for migration. You should only purchase preconditioned beetles.
Lacewings
(Green Lacewing Predator on Soft-Bodied Insects)
Lacewings are a predator for soft-bodied insects. These green insects lay their eggs on silken stalks attached to either stems or leaves. Voracious larvae emerge from the eggs to feed on mealybugs, spider mites, insect eggs, aphids, scales and thrips. If your crops have sticky or hairy leaves, this predator may have trouble locating prey.
Approximately three weeks before pupating, the larvae feed in their cocoons. The cocoons are attached to the leave’s undersides. Lacewings can be purchased as eggs or larvae in individual cells because they are cannibalistic.
Flies
Aphidoletes Aphidimyza (for Aphids)
This predatory midge consumes more than 70 different species of aphids. The adults are approximately 2.5 millimeters in length with a slender body and long legs. Most of the activity occurs at night. Aphidoletes live between seven and 10 days, often feeding on honeydew. Females use the honeydew smell to locate aphid colonies to deposit their eggs.
Once the midge larvae locate an aphid, a paralyzing toxin is injected, dissolving their prey’s body contents. The mouthparts of the midge larvae are attached to the aphid to consume the dissolved contents. To finish developing, each larva requires roughly five aphids. If available, the larvae might kill as many as 64 aphids. The larvae are initially transparent orange.
Depending on the food consumed, the larvae turn gray, brown, red or solid orange. In approximately seven to 14 days, the larvae mature to a length between two and three millimeters. They then fall into the soil from the plant and make cocoons from the soil particles. The emergence of adult midges from the cocoons requires 7 to 10 days.
Hibernation for larvae begins during late September when the days are shorter and the temperatures lower unless 6-watt bulbs are used for supplemental light every 30 feet or 100-watt bulbs every 65 feet. During the fall, aphidoletes tend to hibernate. For fall crops, your best choice for biocontrol are aphelinus abdominalis. This predator is extremely effective when used for aphid hot spots.
The key benefit of aphidoletes is the ability to use them for numerous crops including cannabis, peppers, cucumbers, tomatoes and eggplant in addition to various species of aphids.
Feltiella Acarisuga (for Spider Mites)
This predatory midge is effective for the control of spider mites. Effectiveness increases when used in combination with predator mites. The larvae consume spider mite eggs. When there are colonies of mites, the effectiveness of feltiella increases. Since feltiella are good at locating hot spots, they can be used with predatory mites with better searching abilities.
Feltiella can be used throughout the year as an effective predator, especially for plants with hairy leaves including tomatoes. If you do not use pesticides and have a high density of spider mites, feltiellas can naturally occur in your garden and greenhouse. The adults are approximately one millimeter in length with a pinkish-brown coloration and long legs.
The adults will not feed, with a life of just three to four days. The optimal environment for these predators is a relative humidity level above 60 percent and a temperature between 68- and 81-degrees Fahrenheit. The conditions tolerated by the larvae is a wider range than the adults. Mite colonies with webbing are actively sought by the females to lay approximately 30 yellow, shiny eggs.
Five to 10 days are necessary for the eggs to hatch. The larvae are approximately two millimeters in length, brownish-yellow and feed on two-spotted mites, nymphs and eggs. The mandibles of larvae are inserted into prey for feeding to suck the contents out. During their development, more than 300 mite eggs are consumed. Development in your greenhouse requires approximately seven days.
White fluffy cocoons are spun by mature larvae along a vein on the underside of the leaves. In your greenhouse, the pupal stages require about seven days. If the conditions are cooler, more time is required. They need to be placed near spider mite concentrations on the ground.
Predatory Mites
Hypoaspis Miles (for Thrips and Fungus Gnat Larvae)
Hypoaspis is a predatory mite for fungus gnat larvae and thrips. This soil-dwelling predator has a brownish coloration, feeds on thrips pupae and is approximately one millimeter in length. According to studies, the populations of thrips can be decreased by 30 to 60 percent with hypoaspis. For thrips biocontrol, this predator should be used in combination with natural enemies attacking all life stages of thrips.
This predator is effective in decreasing the larvae of fungus gnats, often offering some control for larvae of shore flies. Hypoaspis remain in the top 2.5 to four centimeters of soil for every life stage. At a temperature of 75 degrees Fahrenheit, the egg to adult cycle requires between 10 and 13 days. Hypoaspis prefer moister potting compost.
Even without food, this predator can live for a maximum of seven weeks. Your soil needs to be moist as opposed to wet. Good activity occurs with a minimum temperature of 60 degrees Fahrenheit.
Amblyseius Barkeri (for Broad Mites)
Amblyseius barkeri is a predatory mite effective for the control of polyphagotarsonemus latus broad mites. This predator will also consume western flower thrips.
Neoseiulus (Amblyseius) Californicus (for Spider Mites and Broad Mites)
This predator mite is effective for the management of spider mites. The effectiveness increases with a minimum humidity level of 50 percent and a maximum temperature of 100 degrees Fahrenheit. Prey is not required for the survival of neoseiulus so you can introduce them as a preventative. Neoseiulus has five life stages requiring between one- and two-weeks dependent on the temperature.
The life of an adult is approximately 20 days, with a maximum of three eggs laid per day. As many as five adult spider mites can be consumed each day although the predator also feeds on larvae and eggs.
Neoseiulus (Amblyseius) Cucumeris (for Thrips)
This is a predator mite consuming thrips. N. cucumeris are less than one millimeter in length with a beige coloration. Once the female mates, eggs are deposited on leaf hairs near veins on the leaves’ undersides. Before maturing into an adult, the larval and two nymph stages are completed. The adult and nymph stages both feed on the larvae of thrips.
The development time necessary to mature from egg to adult at a temperature of 77 degrees Fahrenheit is approximately six to nine days. Prey is killed by the mites when the thrips are pierced, with the contents of their body sucked out. Thrips eggs and larvae on flowers and foliage are attacked. To achieve effective control, you need large numbers.
Adult and second instar thrips use their abdomens to strike out for defense against mites. For maximum effectiveness, time your introduction with the appearance of first instar larvae. This predator might also consume spider mite adults and eggs. You can introduce N. cucumeris for successful thrips control on greenhouse eggplant, peppers and tomatoes.
Introduce this predator as a preventative measure or when your populations of thrips are low. The mites lack effectiveness as a rescue treatment. For vegetable production houses, use virus indicator plants when Necrotic Spot Virus INSV has occurred in the past. Indicator plants with a high vulnerability to INSV ensure you have an early thrips warning for proper detection.
Specific varieties of petunias are an extremely effective indicator for Blue Madness and Carpet Blue plants. Virus symptoms readily appear on petunias as little black or brown spots. This is not an effective virus reservoir but if you remove infected leaves, you can use them all season.
Amblyseius Swirskii
Amblyseius swirskii is an extremely effective generalist predatory mite that can be used to contain immature thrips, cyclamen mites, two-spotted spider mites, broad mites, and whiteflies in fruit, ornamental and market crops.
Adults are pear-shaped, 0.5 mm long, with long legs. The eggs are transparent and round and 0.14 mm in diameter. A. swirskii lay their eggs on leaf hairs and along the veins on the inner surface of leaves. Eggs hatch in about 3 days.
Like other generalist insect predators, A. Swirskii can sustain its population even when food sources are no longer present on the plants and will start working as soon as pests begin to surge. A. swirskii is not susceptible to diapause so it can be introduced in the winter. It is also tolerant of high temperatures. A. Swirskii needs more heat than Neoseiulus cucumeris to develop fully.
Phytoseiulus Persimilis (for Spider Mites)
This predatory mite will consume spider mites and is key to controlling spider mites for numerous crops including pepper, squash, flowers, tomato, cucumber and beans. The adults have a shiny orange coloration with a pear shape. During the nymphal stages, the mites are pale salmon. The legs are long with a more slender body than phytophagous mites.
Oval shaped eggs are deposited by phytoseiulus adults as opposed to the round eggs deposited by spider mites near the colonies. Five days are required to develop from eggs to adults at a temperature of 86 degrees Fahrenheit. If your humidity level is more than 60 percent with a temperature under 86 degrees Fahrenheit, the development is usually quicker.
Phytoseiulus eggs will desiccate at low humidity levels. You can extend mite activity by spraying water using high pressure with a fine nozzle. The adults feed on spider mites at every stage but the nymphs only consume protonnymphs, larvae and eggs. Once the prey has been located, the mite is killed by the predator and the body contents consumed. If you see webbing, the spider mite population is high.
In this instance, compatible soft pesticides may be necessary before predatory mite introduction. Repeated phytoseiulus egg applications are required if there is a new infestation. Without prey, the predators will starve.
True Bugs
Orius Insidiosus (Predator of Small Soft-Bodied Insects and Mites)
Orius Insidiosus are predators of soft-bodied and small mites and insects. This minute pirate bug is effective for consuming immature and adult thrips in addition to other prey including spider mites, aphids and little caterpillars. True bugs have a length of two millimeters, white wing patches, black coloration and an oval shape. The wings are extended beyond the body’s tip.
The nymphs are wingless, move quickly, have a teardrop shape, and conspicuous red eyes with an orangish-yellow to brown coloration. Both nymphs and adults have a lengthy feeding tube referred to as a rostrum capable of folding beneath the body. One to three eggs are laid each day by females embedded in veins or petioles on the leaves’ underside.
Adults reproduce the most efficiently during long days with high humidity levels. The time required to develop from an egg to an adult is roughly three weeks with a temperature of 77 degrees Fahrenheit. The life of an adult is three to four weeks. The adults feed on thrips at all stages. Only thrips larvae are consumed by the nymphs. Once prey is located, beaks are inserted by the bugs to drain the bodily fluids.
If there are no thrips, the O. insidiosus will consume pollen. This predator is most effective when used as a preventative measure.
Parasitoids
Parasitoid Wasps
Aphidius Colemani (for Aphids)
The aphidius colemani is a black, slender wasp about two millimeters in length with conspicuous wing venation, long antennae and brown legs. The male has a rounded abdomen, while the females are pointed. This small parasite will attack melon and green peach aphids. Eggs are laid by the females inside of every aphid host. Both pupal and larvae development occur within the host. This process kills the aphids.
When the adult wasp leaves the body of the aphid, a brown shell, referred to as an aphid mummy, is left behind. The complete development of the aphidius colemani requires 14 days at a temperature of 70 degrees Fahrenheit. The lifespan of the adult is between two and three weeks. The predator needs to be released onto plants all over your greenhouse.
Aphidius Ervi
Aphidius ervi is similar in appearance and life cycle as A. colemani but it is about twice its size. It is used to control potato aphids and, just like A. colemani, leaves behind a brown aphid mummy.
Aphelinus Abdominalis (for Aphids)
The aphelinus Abdominalis is a parasitoid wasp used to control potato aphids. The wasp has a similar life cycle and appearance as the aphidius colemani but is approximately twice as big. Just like the aphidius colemani, a brown aphid mummy is left behind after the emergence of this predator. The wasp is approximately three millimeters in length with short antennae and legs. The female has a yellow abdomen and a black thorax.
The males are smaller than the females with a darker abdomen. You can use these predators for controlling the bigger aphid species including glasshouse potatoes aphids and potatoes aphids. Once the female finds prey, an egg is inserted into the aphid. Aphids can be parasitized by female aphelinus abdominalis during every stage, even the winged adults.
Once the development of the wasp larvae in the aphid’s body is complete, it is transformed into a black mummy. The new adult emerges by chewing a hole in the exoskeleton of the aphid. Aphids not yet parasitized are also fed on by the aphelinus abdominalis adults. The adult females remain active for as long as eight weeks. During this time, aphids will continue to be fed on directly by the pests and parasitized.
You should introduce aphelinus abdominalis as soon as you see aphids appearing. Although they do not work as quickly as aphelinus abdomi, the advantage is they remain active for as long as two months. You release these predators directly into your crops.
Dacnusa Sibirica (for Leaf miners)
The dacnusa is a parasitoid wasp naturally found in Europe and North America. This predator is between two and three millimeters in length, has extremely long antennae and is used for leafminers. The wasp can find leafminers when the density is very low. The dacnusa searches mostly within your lower crop canopy. Eggs are deposited by the females into the leafminer larvae, usually of the second or first instar.
Once the new wasp has hatched, their life cycle is completed while they are still in the leafminer’s body. This process kills the leafminer. The wasp requires between 17 and 19 days to develop at a temperature of 68 degrees Fahrenheit. Dacnusa can hibernate within the leafminer pupae.
Diglyphus Isaea (for Leaf miners)
Diglyphus is a parasitoid wasp between two and three millimeters in length, with black coloration, naturally found in North America and used for leafminers. The sting of the female occurs during the leafminer larvae’s second or third instar resulting in paralysis. An oval egg is then deposited in the mine, close to the leafminer laiva. Once the diglyphus has hatched, it begins feeding on the leafminer.
Diglyphus populations increase extremely quickly, so you can control heavy infestations of leafminers within a short period of time. If your density of leafminers is lower, prey can be located much more efficiently with dacnusa sibirica. Dacnusa and diglyphus have different actions.
Encarsia Formosa (for Whiteflies)
The encarsia formosa is a parasitoid wasp used to control whiteflies. The adult females are approximately 0.6 millimeters in length. At a temperature range of 61 to 83 degrees Fahrenheit, the wasps will live between 15 and 30 days. Longevity is decreased by higher temperatures. The wasps have yellow abdomens and black thoraxes and heads.
The males rarely occur but are darker than the females. The females reproduce without mating or parthenogenetically. Energy is obtained by the adults through the consumption of the honeydew production of the whiteflies and whitefly larvae. Plant canopies are searched by the females for whitefly larvae. Once the right sized parasite is located, an egg is inserted by the female into the encarsia larvae.
This completes the development of the wasp from an egg to an adult inside of the parasitized whitefly. The eggs are usually inserted into the third or the beginning of the fourth instar larva. Every adult female lays approximately five eggs each day, with around 59 during their life. Eight days after the whitefly pupae have been parasitized, to starts turning gray. Whitefly pupae in good health are creamy white.
As the growth of the encarsia larvae continues, the color of the whitefly pupal case changes from gray to black. This makes it easy to recognize a parasitized pupal case. A completely blackened appearance is a good indication pupation of the encarsia larvae has occurred. A mature wasp emerges within a period of seven days by chewing a round hole through the top surface’s head portion of the pupa.
The encarsia has a complete life cycle of roughly 19 to 21 days when the temperature is 73 degrees Fahrenheit.
Methods for Releasing Encarsia
You can use one of four different encarsia release methods for controlling whiteflies in your greenhouse. The development of these methods took place in Europe for commercial vegetable producers. These four methods are Pest in First, Inundative, Banker Plants and Dribble. The success and effectiveness of these methods are based on sooty mold development and honeydew levels developing on both fruit and foliage.
You will have achieved whitefly control in your greenhouse when the levels of sooty mold are accepted for marketable products.
Dribble Method
The dribble method involves introducing parasitoids each week prior to planting. You will be anticipating whitefly populations developing naturally. You can also introduce encarsia when you initially observe whiteflies. Once you have observed the different stages of whiteflies, you need to introduce parasitoids every 14 days until you observe parasitized whitefly pupae at high levels throughout your crops.
At this time, you can stop new introductions. This method is generally more cost-effective as opposed to the introduction of encarsis on a weekly basis throughout your crop cycle. The method most often used for Pennsylvania greenhouses is the dribble method.
Banker Plants Method
The banker plants method involves the use of established parasitoid colonies reared on plants infected with whiteflies being introduced into your crops. You can use mesh screens for cage banker plants for the containment of whiteflies. These tiny parasitoids will only be able to disperse into your production section.
The banker plants system might necessitate your other growth chambers or facilities establishing biocontrol and pests on the banker plants. The advantage of this method is ensuring an onsite and sustainable supply of parasitoids.
Inundative
For this method, you need to regularly introduce many encarsia. This method is effective if you are not expecting a need to establish and reproduce biocontrols. The inundative method is frequently used for both short term and ornamental crops. Inundative biocontrol introductions might not be cost-effective.
Pest in First Method
The Pest in First method involves the introduction of adult whiteflies at a fixed rate throughout your crop when installing transplants into your production houses. Regular intervals are then used for the introduction of encarsia when you observe the development of whitefly nymphs. Due to concerns regarding the release of pests directly into crops, this method is not frequently used.
Prior to using any of the four introduction methods, you should talk to your supplier. You will be provided with advice regarding how many encarsia are required for your crop. Since the basis for the actual number is your population of whiteflies, you need to scout and observe your crop carefully. You can also use any of these methods for other predators and parasitoids.
Eretmocerus Eremicus (for Whiteflies)
As a parasitoid wasp, eretmocerus eremicus is used for whiteflies. It is particularly important to correctly identify the whitefly species you need to control. Although both eretmocerus and encarsia are parasitoids for every species of whiteflies, encarsia is more efficient for the control of whiteflies in your greenhouse. If the issue is Silverleaf whitefly, encarsia is a more effective method of control.
Just like with encarsia, whitefly nymphs are fed on by the adults. The adults also lay eggs beneath or in the nymphs. In most instances, the resistance of eretmocerus to pesticides is greater than encarsia with the adults more active when the temperature is higher. Eretmocerus is a good choice during the spring when the temperatures of your greenhouse exceed 80 degrees Fahrenheit.
The female adult eretmocerus is approximately one millimeter in length, has thick antennae, green eyes and a pale lemony yellow coloration. The males are a yellowish-brown with elbowed and longer antennae. Their development can occur during any whitefly nymph instar, although the second or the beginning of the third instar stage is preferred. Whitefly nymphs are also fed on by the adult wasps.
The eggs of the eretmocerus are laid beneath the host. The new larvae emerging have hooklike mouthparts used to attach themselves to the bottom of the whitefly nymph. This is where a small hole is chewed by the eretmocerus. The eretmocerus larva enters the whitefly nymph within three to four days. The parasite will remain dormant until the pupation of the whitefly.
Once the pupation stage is reached, digestive enzymes are released by the eretmocerus larvae to start ingesting the pupa body parts containing a semiliquid. Two weeks after the whitefly pupa is parasitized, the color turns yellow. When the pupae are parasitized by encarisia, the color becomes black.
To enable the eretmocerus to exit the host, a little round hole is chewed at the top of the pupa. The complete life cycle requires between 17 and 20 days. This is dependent on the instar in which the whitefly was parasitized and the temperature. You should introduce eretmocerus during curative levels when you initially identify the stage of the whitefly.
Continue introductions weekly until 80 percent of the parasitization has been completed for the whitefly pupae. In order to monitor, you will require a hand lens between 16x and 20x. Once you stop introducing predators, it is important to continue monitoring the populations of whiteflies.
Leptomastix Dactylopii (for Citrus Mealybugs)
As a parasitic wasp, leptomastix dactylopii are used for citrus mealybugs. The parasitoid wasp is three millimeters in length and moves through hopping and short flights. In most cases, the females are longer than the males with straight, long and non-hairy antennae. The antennae for the males are slightly bent and hairy. Females live for approximately 27 days, laying between 50 and 100 eggs during this time.
If you need to control citrus mealybugs, leptomastix is extremely efficient. They are attracted to the smell of unparasitized mealybugs. The female predators search for mealybugs in the larger stages. Once a suitable host has been located, an egg is laid by the wasp inside the body of the mealybug. As the larvae develop, the mealybug is turned into a barrel-shaped, brown and legless mummy.
This completes the life cycle of the predator. As soon as the leptomastix emerges from the parasitized body of the mealybug, it begins feeding on the mealybug’s honeydew as an adult wasp. After feeding, the parasite begins the next generation. At a temperature of 75 degrees Fahrenheit, roughly three weeks are required for completion of the life cycle.
If you have a heavy population of mealybugs, you can increase effectiveness by combining this parasite with an introduction of Cryptolaemus. It is especially important your identification of mealybugs is correct because only citrus mealybugs will be parasitized by the leptomastix.
Metaphycus Helvolus (for Soft Scales)
This parasitoid wasp is used for soft scales. The predator wasp is two millimeters in length. When the metaphycus helvolus is introduced at the correct time as a preventative measure, it is extremely effective. If you have excessive deposits of honeydew, this minute sized wasp can become trapped. You should rinse the honeydew off your plants prior to introducing this predator wasp.
Another option is the introduction of predators that will not become trapped in the honeydew. One egg is placed by the adult wasp beneath each scale. When the egg hatches with the emergence of larvae, the scale is consumed from within. After the metaphycus helvolus development has been completed, a new wasp will emerge from within the now empty scale cadaver.
This parasitoid requires approximately 42 days for development. The lifespan of the adult is roughly two months. You can establish optimum environmental conditions with a relative humidity level of approximately 50 percent and a temperature between 73- and 87-degrees Fahrenheit.
Trichogramma Spp. (for Caterpillars)
This parasitic wasp is used for caterpillars. One of the most effective and popular control methods for caterpillars is the trichogramma egg parasitoid. This wasp is 0.9 millimeters in length with short antennae and a compact body. Eggs are laid by the females within the eggs of numerous and destructive types of caterpillars. The life of the wasp is completed within the parasitized egg of the caterpillar.
Only caterpillar eggs will be parasitized by this wasp. This means predicting the presence of females capable of laying eggs prior to the introduction is important. You can accomplish this with pheromone traps. You need to place the trichogramma throughout your crop so the wasps can start looking for host eggs among the plants after emergence.
Ant control is important because ants will begin feeding on the eggs. Most biocontrol suppliers offer numerous species including T. pretiosum, T. minutum and T. brassicae.
Parasites
Entomopathogenic Nematodes
These microscopic nematodes can be predaceous, free-living or parasitic. The simple roundworms do not have appendages or segments. The nematode is an entomopathogenic insect-parasitic symbiotically associated with bacteria lethal to numerous soil-dwelling insects. Nematodes do not have any effect on either plants or vertebrate animals.
There are two insect-parasitic nematode generas for biocontrol, Heterorhabditis and Steinernema. For this reason, the parasites are host specific. Purchasing the right nematodes for your pest issue is important. These types of nematodes have been successfully used for the control of soil-dwelling pests located in turf, strawberry, mushroom and greenhouse industries.
Due to the high safety degree, applications of nematodes are exempt from worker protection standards and reentry intervals. Safety equipment such as a mask is not required. You can apply nematodes in a similar manner as many conventional pesticides including the use of a backpack sprayer, fertigation system or pull-behind sprayer.
If you apply them to the soil, the pest is surrounded by the nematodes prior to entering through the openings in the natural body. Once the nematoid has entered the body, the release of symbiotic bacteria from the nematode’s gut quickly multiplies resulting in the death of the insect in a period of 24 to 48 hours. The nematodes then develop into adults by feeding on the broken-down tissue found within the insect cadaver.
The production of a new nematode generation occurs within a period of two weeks. The emergence of thousands of infective juveniles emerges from the insect of the cadaver. The juveniles then look for a fresh host. When Steinemematid nematodes have killed an insect, the appearance is a yellowish-brown coloration. A red appearance with tissue like gummies results when Heterorbabditids have killed the insect.
Heterorhabditis Bacteriophora (for a variety of soil dwelling hosts)
One of the entomopathogenic nematodes is heterorhabditis bacteriophora. An entomopathogenic nematode will attack numerous soil-dwelling hosts including fungus gnats, grubs and caterpillars. This type of nematode is most often used for the control of root weevils in containerized soil. This is especially true for black vine weevils.
Heterorhabditis bacteriophora is used for attacking numerous pests in greenhouses, tree nurseries, ornamentals and strawberries.
Steinernema Carpocapsae (Entomopathogenic Nematode)
You can easily mass produce steinernema carpocapsae. Of all the entomopathogenic nematodes, more studies have been conducted on steinernema carpocapsae than any other. The formulation is a moist sponge or partly desiccated state. Steinernema carpocapsae is the most effective for insects feeding on the soil or soil surface including armyworms, stem borers, webworms, cutworms, billbugs and fleas.
Steinernema carpocapsae belong to the ambusher species. This predator stands in an upright position on its tail close to the surface of the soil to attach to hosts as they pass. It is available ideal for greenhouse, crops, ornamentals, turf, small fruits and vegetables. If the temperature is below 60 degrees Fahrenheit it will not function well.
Steinernema Feltiae (Entomopathogenic Nematode)
Steinernema feltiae is an entomopathogenic nematode you use for controlling flies or dipterous insects including mushroom flies and fungus gnats. Once the fungus gnat larvae have been infected, the healthy white color changes to a yellowish-brown. If the temperature of your soil is lower, steinememafeltiae is more effective than using S. catpocapsae due to an active temperature range between 50- and 86-degrees Fahrenheit.
The application directions are on the label. Once the suspension is reached, the nematodes are applied to the surface of your soil or compost as a drench. Prior to and after applying, make certain to water well.
Pathogens
Fungus
Beauveria Bassiana (Pathogen for Insects)
Beauveria bassiana is a fungus pathogenic for insects. In order to be effective, there must be direct contact between the fungal spores and the insects. During the attachment of the spores to the insect cuticle, germination occurs resulting in the fungus growing within the body cavity. This fungus is intended to be used as a preventative as opposed to a rescue treatment.
You may need to use successive treatments to obtain your desired level of control. You need to allow between seven and 10 days to kill the insects. You should not use Beauveria bassiana for controlling heavy populations of pests.
Paecilomyces Fumosoroseus (for Whiteflies)
This fungal insect pathogen can be used effectively for whiteflies. The action is like Beauveria bassiana to produce interior scapes in your greenhouses. Although available in most states, the formulation is currently unregistered to use in Pennsylvania.
