Beneficial insects in the garden (part 1)
How to use biological methods of plant protection
Insects that feed only on plants are called phytophages (from the Greek. phyto - plant, phagos - devour). Predatory and parasitic insects that feed on phytophages are called entomophages (from the Greek. entomo - insect). Entomophages are gardeners' helpers, as they exterminate plant pests. The most common entomophages of the North-West region are ladybugs, otters, lacewings, sirphid flies (or hoverflies), tahini flies, earwigs, camels, predatory bugs, ground beetles.
Most entomophages are insects that have a complete transformation: (egg) → (larva) → (pupa) → (imago, or adult insect). Nature demonstrates a stunning variety of the appearance of entomophages, an amazing variability of the image of an insect at different stages of its development, different duration of development cycles and individuality in behavior. The methods of parasitizing are striking in variety, ingenuity and cruelty.
All entomophages are united by a predatory way of life of larvae and feeding of imago with nectar and pollen of flowers..
Most imago entomophages do not lead a predatory lifestyle. The foodstuffs of adult entomophages are nectar, pollen from flowering plants and honeydew (non-flowering nectar arising from the concentration of plants), which support the vitality of insects and provide their body with the compounds necessary for breeding. For predatory adults (for example, the adults of ladybirds), nectar and pollen from flowering plants are an indispensable food supplement that replenishes the insect's body with compounds necessary for breeding offspring.
After the pupa turns into adults (metamorphosis), before scattering in search of new habitats (and for insects with one offspring per summer, wintering places), entomophages feed on nectar and pollen from flowers, which they first look for in the immediate vicinity of the metamorphosis site. Entomologists cite data that insect feeding on nectar and pollen lasts 7-10 days (in some species, up to several weeks). It increases the lifespan of entomophages, has a positive effect on their health and fertility. Mating of these insects often occurs near nectar feeding sites. A fertilized female entomophage in the neighborhood closest to the place of breeding is looking for places of accumulation of food (aphids etc.) and lays eggs there. If there are no such places nearby, then the natural desire to provide food for its offspring pushes the female to search for new, favorable places for this. Probably, like in birds, memorization of "native places", the memory of which in some insects persists for several years, occurs precisely during feeding and breeding near the place of metamorphosis.
In the North-West region, adults of entomophages can be found in summer in meadows, in forbs along rural and forest roads, in glades, forest edges. Most often, entomophages visit flowers of plants from the family of umbelliferae, legumes, complex and cruciferous plants. The researchers found entomophages from 5 orders and 12 families on nectar-bearing plants. The most numerous were the hymenoptera, insects of the parasitic ichneumon family, gall-moths, ladybugs, lacewings, and sirphids.
In some species of insects (for example, ladybirds, butterflies, etc.), females are distinguished by an amazing attachment to the places once chosen for laying eggs. These places remain unchanged for a long time and, as a rule, are represented by the same plants or bushes that are not in the depths of the forest or fruit plantations, are not in the sun, but have sufficiently good illumination. This selectivity leads to the fact that egg-laying sites are concentrated on a few plants that are especially attractive for insects and, as a rule, are located at the edges of the forest, along the borders of garden plantings and others, where insects under the canopy of plants can find secluded places and “lace penumbra ".
After many years of research, entomologists have selected species of nectar plants that have a long flowering time and attract pollinating insects and entomophages. (see table 1).
|Plant types||Nectar-bearing plants attracting pollinators and entomophages|
|Annual plants||Anise, chervil, coriander, dill, savory, legumes|
|Biennial plants||Cumin, parsley, parsnip, carrot, onion, celery, oat root, scorzoner, mustard, shepherd's purse|
|Perennial plants||All meadowsweet, volzhanki, elecampane, decorative bows, lovage, pupavka, rudbeckia, angelica, eremurus, oregano, lemon balm, mint (pepper, lemon, etc.), hyssop, marjoram, garden fennel, clary sage, clover, vetch, alfalfa|
|Meadow herbage||Wild cumin, chamomile (odorless, popovnik), yarrow, clover, dandelions, common goldenrod, willow-leaved tea (narrow-leaved willow herb), daisies, runny (runny is a good nectar plant and is valued equally with ivan tea)|
Nectariferous plants are a food base for imago entomophages, which need food with flower nectar and pollen from spring to autumn to continue their offspring, since some of them complete a cycle of complete transformation 5-7 times during the season, and up to 7-9 times in a favorable year. time.
To attract beneficial insects to the garden, you need to plant nectar-bearing plants in the garden, create grasses that attract entomophages along the lands, roads, and ditches bordering the garden. Nectar-bearing herbs in the garden and on the land adjacent to the plot play the role of a luring "green belt" for beneficial insects. This technique manages to significantly limit or even completely exclude the use of chemical methods of plant protection.
Early waking predators (for example, sirphids) need early flowering nectar-bearing plants to create offspring. It can be dandelions, lungwort, medicinal galega, crested beetles, Suvorov onions, maples that bloom early in our country, elderberry. Common hazel is one of the most important pollen producers. In early spring, insects take from it high-quality bee bread with a high content of proteins and vitamins.
Many entomophages love to visit flowers of spicy herbs, so it is reasonable to have clumps of parsley, dill, mint, oregano, lemon balm, caraway seeds, marjoram, etc. near or under fruit trees.
Onion inflorescences are very attractive for predatory insects. Curtains of large inflorescences of decorative onions, Moli's onions, Suvorov's onions, elegantly flowering borders of chives decorate the garden and attract entomophages. Ornamental onion varieties bloom at different times almost throughout the summer: from May - early June to August. The Suvorov onion blooms in the first half of May and is the earliest of all onions. The green of its powerful leaves in spring breaks through right out of the snow, has a garlic flavor and is very useful. On the caps of flowers of perennial bows, ladybugs and sirphids predominate.
Meadowsweet and Volzhanki (Aruncus) love humid shady places (although they grow well in the sun, if they have the opportunity to get drunk). They have a long flowering time and are adored by insects, luxurious inflorescences with a delicate aroma. The size of the inflorescences of some Volzhankas reaches 40 cm or more.
Tansy attracts ladybirds, cunning bedbugs, small parasitic wasps, lacewings, predatory flies. The navel is attractive to parasitic wasps and predatory flies. Cumin during flowering is visited by cunning bugs, spiders, small wasps, sirphids, lacewings.
Flowers of fragrant dill are loved by ladybugs, sirphids, small wasps, spiders. Blooming mint is attractive to predatory flies and spiders. Many types of legumes (crimson clover, creeping clover, vetch) provide beneficial insects with constant food and moisture.
Tansy, sweet clover, navel, common goldenrod bloom for a long time from year to year. When mowing in gardens, the growing areas (clumps) of nectar-bearing plants should be preserved. It is advisable to delay the mowing of the grass during the flowering period for 3-4 days.
Read the second part of the article Beneficial insects in the garden
member of the gardeners section of the House of Scientists. Gorky
How to attract beneficial insects to your garden
In Europe, the owners of garden plots place special houses - shelters for insects, like nest boxes for birds. They are done very simply, and some "models" will not only help protect the garden from the invasion of pests, but also decorate it. Bricks, old boards, straw, bamboo tubes - you don't need anything special. Knowledge of beneficial insects' habits and imagination will turn old junk into conceptual design objects.
Who should you try to attract to the garden? First of all, it must be said about ladybirds. This little bright bug is known to everyone. Not everyone, however, knows that creatures harmless to humans are gluttonous predators, zealously destroying smaller animals, mainly aphids. The appetite of the larvae is especially great. The ladybug larva is not a very pleasant creature without wings, with bright spots on the dark back. But when you see such a "worm" on the sheet, resist the temptation to destroy it. In many countries, ladybirds are bred specifically for sale to gardeners. Several dozen bugs are capable of causing serious devastation in the ranks of aphids.
Another enemy of aphids is the lacewing. An adult insect resembles a moth with delicate transparent wings folded into a house, and shiny golden-green eyes, its larva is not inferior in its predatory habits to the larva of a ladybug. With its huge - for its size, of course, with curved jaws, it grabs aphids and sucks them out, leaving only an empty skin. For its habits, the lacewing used to be proudly called "a lizard lion". The grown larva, like a fur coat, is covered with a layer of empty skins, which it carries on itself for protection from the sun and for better camouflage.
Many species of flies feed on nectar and live on flowers, pollinating them like bees. Often they are very similar in appearance to bees, wasps and bumblebees. The larvae of some hoverflies are also predators, crawling over plants in search of prey.
First and foremost, remember that any massive insecticide treatment leads to the death of not only pests that quickly restore their numbers, but also their useful and beautiful neighbors, which multiply much more slowly. Houses for "ladybugs" and "butterflies" sold in Europe usually look like little birdhouses or letterboxes. They are sometimes interestingly decorated and serve as a decoration for the suburban area. You can make such a house yourself. However, it must be admitted that this is a purely decorative structure, since neither ladybirds nor butterflies need houses in summer. If you do not specifically attract them with ferromones or a nutrient mixture, they will only get there by accident.
As for hibernation, hibernating insects really need a shelter where they can survive the cold. In our climate, it is advisable to arrange such shelters closer to the ground so that they are covered with snow. Old woodpiles, boards laid on the ground, pieces of bark, heaps of leaves and shavings gather a motley company under their roof. Here and centipedes - drupes and kivsyaks, worms, and, of course, insects - ground beetles, various larvae, earwigs. Earwigs are usually considered pests, although they begin to damage plants only if they multiply strongly. At the same time, the earwig is not averse to hunting harmful insects.
Several cardboard tubes with a diameter of a little finger or a pencil and a length of 15–20 cm, tightly closed at one end, will serve as an apartment building for single bees. Unlike social bees and wasps, they are completely non-aggressive even near their home, while pollinating plants no worse than a domestic honey bee. Moreover, some types of bees have become rare in the European part of our country. A bundle of tubes (in a horizontal position) can be hung under the roof of a house, a shed, in any other place protected from rain. Or make a house as for
ladybugs and fill it with tightly packed tubes. Instead of paper tubes, you can take pieces of stems of umbrella, reed, or other similar plants. It is in them that solitary bees live in nature. You can drill holes in a piece of wood. Such a structure is called "Fabre's hive" - the famous French naturalist Jean-Henri Fabre was the first to decide in such a simple way to settle single bees literally under the roof of his house. It is very interesting to observe their work and habits.
Insects need not only shelter, but also food. With the exception of predators, most of the creatures mentioned here feed on the nectar of flowers. They are not attracted to different types of plants to the same extent. Bees, riders, flower flies love most dill and other umbellates during flowering, yarrow,mustard,coriander,mint... If there is a curtain or two of such plants on the site, the presence of various insects is ensured there.
Council of the reader of the "Sadovnik" magazine
Natalia Podlesnaya, Kiev
There will be fewer pests if you leave enough weeds in bloom. For a while, I experimented with an assortment of wild plants that could take the blow of aphids. Now I am pleased to recommend them to you. I still have uncut curtains shepherd's purse, species Achilea, wild carrot, annual cornflower... Plant a bush in the rose garden thistle... It is beautiful, architectural and will collect all the unpleasant living creatures from roses... Hordes of ants feed on aphids on the clumps of these plants throughout June and half of July, and aphids serve as complementary food for predatory insects. When the "turn" of cultivated plants approaches, there are already enough predators in the garden to keep the plantings clean. This way I maintain bio-equilibrium without using chemical protection products in my garden.
The relationship between some insects has led to the full use of one species of another, i.e. parasitism.
The word "parasite" (parasite) is of Greek origin. Even in the days of the ancient Greeks, this was the name for people living at the expense of others. Later, ancient medicine gave the name "parasite" to an organism that feeds on another organism, inside which it lives.
Among insects, there are parasites that live both inside the host's body (endoparasites) and on its surface (ectoparasites).
The larvae of external parasites feed on the contents of the host's body through wounds inflicted on it by the oral apparatus. The action of insect parasites on their host is slower than that of predatory insects.
Parasites, using the host's body for nutrition and development, slowly lead it to a morbid state and death. In addition, internal parasites use the host's body as their habitat.
Having finished development, different types of endoparasites leave the host's body in the stage of larvae that have completed development, or as adult insects. To do this, they gnaw through the host's outer cover.
Adult parasitic insects lead a free lifestyle, feed on nectar and pollen of plants, dew drops. Nutrition prolongs their life and increases fertility. Unlike their larvae, they do not lead a parasitic lifestyle and are persistently looking for a host in order to attach their offspring.
Parasitic species have developed adaptations to their host in developmental biology and body structure, functions and behavior that are characteristic of the parasitic lifestyle. Thus, during the period of conjugate development in the process of evolution of the parasite and the host, their specialization was clearly indicated.
According to the degree of specialization, parasitic and predatory insects are divided into:
- highly specialized, adapted to one or two close, similar hosts - herbivorous insects
- polyphagous, having a wide range of hosts, belonging to various species of different orders of insects.
There is also an intermediate group of relatively specialized parasitic and predatory insects. They attack insects belonging to different genera within the family.
Among the parasites there are primary ones, living off herbivorous insects, and secondary ones, charging the larvae or pupae of primary parasites, including those in the host's body.
TrichogrammaTrichograms parasitize insect eggs. Photo: Bugs For Bugs
The name "Trichogramma" is used to designate a number of insects from the Trichogrammatid family, to which several species belong. Their biology is in many ways similar. All of them are polyphagous and parasitize in eggs of more than 200 host species. They have intraspecific forms that have adapted to certain conditions. These parasitic insects are often called egg-eaters.
These are very small (less than 1 mm) hymenoptera insects. The color of the body, depending on the type, is brown, yellow, gray, the eyes are red. The abdomen is almost cylindrical, rounded. The forewings are wide with a rounded apex and short fringes. The hind wings are narrow, the antennae are geniculate.
They lay their eggs inside the eggs of various species of butterflies, including the moth. Having found an egg of a harmful insect, the female of Trichogramma pierces the shell of the egg and puts her tiny testicle inside it with the ovipositor. Then he proceeds to the same operation on the next found egg. And so from morning until dusk in search of the next egg-laying pests, until the entire set of sexual products ends. Fertility of the female - maximum - 80 eggs.
At a temperature of + 12-13 ° C, adults are inactive. With an increase in temperature to + 17-18 ° C, the activity of females increases, and at + 25-30 ° C they already work within a radius of up to 30 m. At a higher temperature, the trichogramma hides in the shade under the leaves of plants. The insect has adapted to the surface lifestyle, which is associated with the habitats of the owners.
The trichogramma larva hatches at a temperature of ° C within a few hours and immediately begins feeding. From the beginning of hatching, it is completely supplied with food. The contents of the host's egg are enough for her to fully develop. At a temperature of + 25-30 ° C, its development lasts from 12 to 18 days, with a decrease in temperature, the duration of development increases.
Having finished development, the larva turns into an adult insect, destroys the egg shell and flies out. In the Trichogramma population, females are usually born. Several days pass, and the fertilized female searches for the host's eggs. This is repeated up to 9-10 times per season.
The life cycle of trichograms is not confined to the development cycle of a particular host. Trichogramma is capable of laying eggs throughout the growing season. Under natural conditions, in spring, at the beginning of summer, the infection of eggs with trichogramma is low, but due to the rapid development and predominance of females in the population, it accumulates in significant numbers by the end of summer.
Trichograms mate without leaving the host's egg
This prompted the idea of the advisability of artificial breeding of egg-eaters and their release into natural conditions so that they quickly multiply by the period of mass egg-laying by most pests of field crops and perennial plantations. Trichogramma overwinters naturally in the host's eggs.
Three types have found practical application - trichogramma ordinary, male-free and yellow moth. Each type of trichogramma has favorite hosts, whose eggs it readily and intensively strikes.
Trichogramma ordinary more than others infects the egg-laying of various types of scoops - cabbage, winter, garden and other pests of field crops.
The yellow moth and maleless trichogramma are adapted to life in tree plantations. Both species, in contrast to the ordinary trichogramma, fly well and parasitize in the eggs of butterflies, preferring the eggs of the codling moth and leafworms.
Trichogramma is artificially bred in biolaboratories and biofactories on the eggs of a grain moth, which is cultivated on barley grain, and then settled in natural conditions.
Fruiting trichogramma species in the amount of up to 1500 individuals per tree are released in three terms. As a result, the damage to the fruits of the codling moth can be reduced by
Beneficial insects in the garden
Many have probably noticed that trees and shrubs growing in natural conditions bloom and bear fruit abundantly almost every year. And in the garden, even with careful care, the aphids will attack them, then the bark beetles. As a result, the yields are low, and the quality of the fruit leaves much to be desired. The reason is that the natural plant community regulates the number and type of its inhabitants and the processes taking place in it. And where a large number of herbivorous insects appear, the number of predatory insects that feed on them also grows. If there are more predators and there is not enough "food" for everyone, some of them move to other places, the rest simply die. This is how the natural balance is restored. The massive destruction of garden pests with all kinds of chemicals leads to the death of beneficial insects that feed on them. The natural balance is disturbed.
Take a closer look at the plants that have been attacked by aphids. Usually lays eggs near her colonies lacewing - an insect with large golden-green eyes and transparent mesh wings, shining with mother-of-pearl. In the Moscow region, there are two representatives of this family: mother-of-pearl lacewing (Chrysopa perla) - with dark spots on the body and a larger tape(Nineta vittata) - with yellowish wings. From their eggs, which are attached to the leaf on thin "threads" about 1 cm long, larvae with powerful jaws appear later. Each is capable of destroying up to 200 aphids per day. They also eat worms, pillowcases and many different small caterpillars.
Unlike lacewings camels(Rhaphidioptera) look unattractive - an elongated body (15–20 mm), an elongated head with filiform antennae, a curved back (in some species its length is 3–4 times its width), two pairs of folded mesh wings. The silhouette of the front of their body resembles the neck and head of a camel - hence the name of these representatives of one of the most ancient groups of insects. Many consider them pests and, when they see them in their garden, try to get rid of them. You don't need to do this. Insects live for about 2.5 months. Females lay eggs under the bark of trees - and the larvae develop there. They are very mobile and not only run forward, but can move backward, hunting caterpillars, aphids, worms and other insects. But most importantly, they destroy the larvae of bark beetles.
Ground beetle gardenon the contrary, it is graceful - if in other beetles all parts of the body are practically not separated from each other, then its head, chest and oval abdomen are clearly distinguished. Ground beetles of various colors are found. In central Russia, the most widespread are ground beetles– garden(Carabus hortensis), with a purple-hued shell and yellow specks on the elytra, and lattice(Carabus cancellatus) - with a light carapace, shimmering silver. Much less common ground beetle brilliant (Carabus nitens) - along the edge of its green, with a metallic shade, a thin golden line runs along the elytra. For all its gracefulness, the ground beetle and its larvae (by the way, rather unpleasant in appearance) are real predators. They destroy slugs, snails, all kinds of caterpillars and pupae. They hunt mainly at night.
One of the varieties of ground beetles - horse beetles (Cicindela). True, unlike most of them, they are active during the day. Horses choose open places and quickly run on the ground, flying over short distances in case of danger. Their larvae build vertical burrows in sandy soil and watch for prey in them - ants and other small insects.
Some species develop in wood or under the bark of rotten trees. clickers(Elateridae) and their larvae - wireworms... They are both herbivorous and predators. The former are considered pests of agricultural plants, including potatoes. The latter destroy xylophages (tree beetles), feed on dead insects and fungal mycelium. They owe their name to the ability to bounce when placed on their backs and make a clicking sound at the same time.
In greenhouses, some species are used to control mealybugs and whiteflies on affected plants. ladybirds (Coccinellidae). Only one larva - gray-blue or black, with yellow or white spots - is capable of destroying up to 7,000 eggs, or 100 larvae, or up to 60 adults per day. The larvae also eat aphids, scale insects, scale insects, spider mites and cushions. Only a few of them are herbivorous.
Insects that protect the garden from pests include hover fly, resembling a wasp in color. It feeds on nectar, but its larva eats up to 100 aphids a day. Predatory mites protect plants from spider mites, and bedbugsthey eat eggs of leaf rollers and moths, and even larger insects like earwigs can become their prey. Some species antshunt moths, scoops, sawflies, silkworms. Tiny (0.2-4 mm) riderslay eggs in the eggs of aphids, silkworms, scoops, and some of them in larvae or even in adult insects. Some of their species are successfully used in biological pest control.
Beneficial insects will never settle on an area treated with pesticides. To attract them, you need to plant nectar plants in the garden - for example, mustard, buckwheat, dill, angelica... In some places, you can leave it bloom dandelionsor yarrow... It is also good to plant a hedge with wildflowers.
Harmful and beneficial insects
Even the most exemplary and well-tended gardens are full of insect pests. But, fortunately, there are many useful inhabitants who are ready to come to our aid if we learn to recognize them and create ideal conditions for them. By entrusting pest control to their natural enemies, we will save ourselves from many problems. In order not to accidentally destroy our tiny allies, let's get to know them better. What are the harmful and beneficial insects that live in dachas near us?
In our gardens, there are a lot of harmful and beneficial insects that feed on plant pests. Let's list the useful ones:
It turns out that these are very useful insects for gardens and vegetable gardens. Russia is home to many species of ladybugs, and all of them are beneficial to plants. Adults and their larvae feed mainly on aphids (they eat several dozen of them a day), but they also do not disdain other insect pests: worms, ticks, beetles, dipters and even young caterpillars. Ladybugs can be attracted to the garden by spraying the plants once a week with lightly sweetened water (1/2 spoon per liter of water).
Both adult ground beetles and their larvae are by nature predators, feeding on various insects, earthworms, snails and carrion. When there is a lot of prey, ground beetles get into hunting excitement, as a result of which they kill more victims than they can eat.
The gardens are home to many different types of garden bugs. It turns out that they are also useful insects in the garden and for the vegetable garden. Adult bugs and larvae, which are similar to their parents, but smaller in size, prey on various harmful insects that have a soft, easily biteable cover. Bedbugs destroy beetles, caterpillars, aphids, spider mites.
Hoverflies belong to the category of Diptera. Adult insects feed on pollen and nectar of flowers, and their larvae prefer aphids, beetles, honey beetles, eggs of Colorado beetles. You can increase the number of hoverflies in the garden by sowing melliferous plants (phacelia, buckwheat, clover, marigold, sunflower).
Among the beneficial insects, lacewing should also be mentioned. They usually feed on nectar and pollen, but they do not refuse pests, especially aphids. Lacewing can be helped through the winter as they are very sensitive to the cold. To do this, in the fall, place a red or brown wooden box filled with dry foliage in the garden. Small gaps should be left between the boards of the box, where the lacewings could penetrate. After some time, the box must be moved to a warm, dry room, and in the spring it must be put back into the garden. The larvae of lacewings are more predatory. One larva can eat up to 450 aphids within two weeks. In addition to aphids, they also destroy beetles, copperheads and leaf rollers.
Among the harmful insects for our gardens and vegetable gardens, black garden ants should be indicated. These are very persistent pests. Moreover, they take care of aphids, drive away enemies such as ladybugs from it, and even transfer aphid colonies to other trees and bushes that are not infected with it. The fact is that in summer the garden ant feeds mainly on carbohydrate food, which is emitted by aphids. Black garden ants live in the ground, and it is very difficult to dislodge them from the beds or greenhouses. Pour boiling water over ant holes, sprinkle with quicklime, use poison baits. Defeat the ants, then there will be less voracious aphids.
We hope that this information about beneficial and harmful insects will be used by our gardeners and gardeners.