Excerpt fromFruit chop Ecology and Management, thing 2: controlling the neighborhood of Pests and also Beneficials by Larry Gut, Annemiek Schilder, Rufus Isaacs and also Patricia McManus

Ecological concept: Natural enemies assist keep pest populations in check.

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Putting it right into practice: Preserve herbal enemies.

Integrated pest management emphasizes the importance of interactions in between pests and also the natural opponents that food upon them. As soon as broad-spectrum insecticides are applied, pest and also non-pest varieties are killed and also the balance the the community is disrupted. Because that example, pesticide use in pear orchards to manage codling moth can additionally destroy the natural opponents of pear psylla. In the lack of its herbal enemies, pear psylla deserve to reach high densities and cause far-reaching damage come the fruit.


There is an excellent potential for biological control of number of fruit pests if populations of predators and also parasitoids are preserved and also enhanced. Because that example, organic control of plant-eating mites is accomplished in plenty of fruit production systems through conserving predatory mites, as well as predacious beetles and bugs. To avoid killing natural enemies of mites, pesticides should be selected carefully. Two classes that insecticides that are very toxic because that mite predators space the pyrethroids and also the carbamates. Organic control of to apologize leafminers by parasitoids is usual in Pacific Northwest orchards, and also has potential in various other areas. To maintain these crucial allies, prevent using moderately and highly toxicity insecticides from mid-June to early on July once adult parasitoids are most active.

Use manage tactics that space the least harmful to natural enemies. Avoid insecticides that are highly toxic to predators and parasitoids. If one of these materials must be used, spray as soon as natural opponents are the very least vulnerable. In general, broad-spectrum insecticides applied early in the farming season, before many natural adversaries have become energetic or moved into the crop, often tend to be less disruptive 보다 those applied later in the summer. Use spot treatments or delayed applications once it appears natural enemies could be may be to administer control. Check out images, more information about natural enemies.


Natural opponents are separated into two main groups: predators and also parasites. A predator lives by capturing and feeding on another species. Predators are usually larger and much more powerful 보다 their prey. Numerous of the most typical predators in fruit manufacturing systems strike a wide variety of pest varieties and help regulate pest population densities. Several are detailed here with few of their food in fruit crops.

Amoebae: Soilborne fungi, bacteriaAnthocorid bugs: Spider mites, thrips, aphids, pear psylla, young scale, miscellaneous insect eggsBigeyed bugs: Lygus bugs, aphids, leafhoppers, spider mitesCollembola: FungiLadybird beetles: Aphids, scale insects, pear psylla, mealybugs, other soft-bodied preyLacewings: Aphids, scale insects, mealybugs, pear psylla leafhoppers, thrips, mitesMirid bugs: Spider mites, aphids, leafhoppers, pear psylla, scale insectsMycophagous mites: Fungi, eg. Grapevine powdery mildewNematodes: Soilborne fungi, bacteria, various other nematodesPredatory mites: Plant-feeding mitesSpiders: Pear psylla, aphids, leafhoppersSyrphid flies or flower flies: Aphids, scale insects


A parasite resides in, on, or with another organism and obtains food and also usually shelter at the host"s expense. Helminth insects and also microbes are essential in the biological control of many pests. Tree pathogens might be taken into consideration parasites that cause condition symptoms in plants.

An insect the is parasitic on various other insects throughout its immature stages, yet is free-living as an adult, is called a parasitoid. Many parasitoids are tiny flies or wasps. Parasitoids space often usual in flowering tree such together fruit crops and also therefore space potentially an extremely beneficial allies that fruit growers. Part parasitoids are specialists, attacking one or a couple of host species, when a few are generalists and use a wide variety of various other insects together hosts. The free-living adults often feed ~ above the nectar provided by flowers. The female parasitoid finds a host and lays eggs. The parasitoid larva develops inside or ~ above the host. At first the larva feeds only on fat tissues, permitting the organize to proceed to grow and also develop. Together the parasitoid nears the finish of that development, it consumes the host"s an important organs, killing it. The parasitoid larva pupates and later emerges as an adult.

The emerging parasitoid often leaves behind telltale signs of the handiwork. When scouting for pests, also watch for parasitoid pupal cases or appearance holes in insect bodies. Try to pick management methods that safeguard parasitoids such as utilizing selective insecticides.

In the diagram,A. A wasp lays an egg in a hold (in this example, an aphid).BandC. Together the hold feeds and also grows, therefore does the wasp larva.D.The parasitoid kills then pupates within the dead host.E.An adult parasitoid emerges from the dead host.


The complying with are usual parasites and some of your hosts in fruit crops.

Aphelinid wasps: AphidsTachinid flies: Caterpillars, beetlesTrichogramma wasps: Moth eggsBacillus thuringiensis (bacterium): Butterfly/moth larvaePseudomonas fluorescens (bacterium): FungiPolyhedrosis virus: Butterfly/moth larvaeBeauveria bassiana (fungus): countless insectsTrichoderma harzianum (fungus): Pythium, Rhizoctonia and also other pathogensAmpelomyces quisqualis (fungus): Powdery mildewArthrobytris (nematode-trapping fungus): NematodesSteinernema (nematode): Insect larvaePasteuria penetrans (bacterium): Nematodes

Parasitic microbes such together fungi, bacteria, and viruses can cause diseases that insects. Bacillus thuringiensis (Bt) is a renowned bacterium that kills insects through a potent toxin. Bt need to be eaten prior to it deserve to kill that host, so sprays should be timed to coincide with heat periods when the target insect is most likely to it is in feeding. Once consumed, the Bt toxin destroys the insect"s gut. Infected insects become lethargic, stop feeding, and also die.

Parasites also keep virus populations in check. Because that instance, the fungus Ampelomyces quisqualis parasitizes powdery mildew mushroom on number of fruit crops. A commercial formulation have the right to be used to slow disease development by to reduce vigor and also spore production of the mildew colonies. Additionally well well-known are Trichoderma species, i beg your pardon parasitize soilborne pathogens such together Rhizoctonia and Pythium.

Even an ext interesting room soil-inhabiting fungi that trap and also devour nematodes with dedicated structures the resemble lollipops and also lassos. Bacteria are likewise known come parasitize nematodes. Because that example, the bacter Pasteuria penetrans strikes the root knot nematode.

Mutually advantageous relationships

Some helminth fungi have actually mutually helpful relationships through plants. Because that example, mycorrhizae space fungi the live within plant roots and also generally have actually a valuable effect top top the plant. They usage their substantial threadlike mycelia to absorb nutrients and water from the soil, passing them on come the plant roots. In return, the plant provides shelter and also nourishes the fungus. Mycorrhizae may likewise protect tree roots against microorganism invasion.

Some insects live together to benefit one another and also this can make pest management an ext challenging. Aphids can regularly be found living in a support beneficial arrangement with swarms of ants. The aphids develop honeydew and also the ants harvest the sugary fluid for food. Worker ants can be watched running in between aphid colonies and also their nests in the soil. In return, the ants defend aphids indigenous predators, and may even carry them come a much better habitat if the tree starts to die. This interaction have the right to lead to rapid rises in insect populations because natural opponents are prevent from regulation the aphids.

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Pathogen and vector relationships

Another crucial interaction among organisms in a fruit crop is the function of insects in dispersing diseases. Blueberry aphids, which are pests in their own right, can also vector blueberry shoestring virus, which reasons malformation the blueberry shoots and leaves and a decline in vigor and productivity. The mummy berry fungus creates a unique alliance with an insect that access time blueberry flower daily. Bees space fooled into thinking that the shoots extended with fungal spores space actually flowers by the distinct UV patterns created by the diseased tissue. The spores, which are produced in a sweet sticky matrix, quickly stick come the bee"s body and are ceded to the stigma wherein infection occurs. Below ground, certain nematodes are additionally vectors for plant pathogens. The dagger nematode have the right to transmit the tobacco and also tomato ringspot viruses to miscellaneous hosts, consisting of grapes. This viruses reason a slow decline of the grapevine.