In what main ways do flower pests harm flowers?
In the previous article we introduced the common pests encountered in potted soil flower cultivation. We all know that pests cause great harm to flowers, seriously threatening their propagation, growth, flowering, fruiting and ornamental value. Today pests have become one of the main enemies of home flower growing and flower production. But many flower lovers still cannot accurately recognize the harm caused by pests, so how do pests "harm" flowers?
Generally speaking, the harm pests cause to flowers falls into three aspects: feeding damage, non-feeding damage and transmission of plant diseases.
1. Feeding damage
Pests can directly damage the roots, stems, leaves, buds, fruits, seeds and other parts of flowers, producing different types of damage symptoms. Because pest mouthparts and feeding sites differ, they display various modes of damage, which can be summarized mainly into the following 6 types.
(1) Chewing
Pests gnaw the leaves, forming notches and holes or eating the leaves completely, leaving only the petioles and veins, seriously affecting the growth and ornamental value of the flowers.
(2) Leaf rolling or leaf tying to build nests
Larvae of tortricid moths often curl leaves and hide inside them to feed; tent caterpillar larvae spin silk webs, tie leaves together to build nests, and feed in groups inside, causing leaves to curl and destroying the normal growth of tender shoots and young leaves.
(3) Leaf mining
Larvae feed between the upper and lower epidermis of leaves, forming winding tunnels;
(4) Borer damage
Longhorn beetle larvae and others bore tunnels in the xylem of the branches and trunks of flowering trees and shrubs, feeding and causing damage; after being attacked the plants age and die prematurely, as shown in the image of boring longhorn beetle larvae.
(5) Piercing-sucking
The damaged parts develop chlorotic spots or yellowish-brown spots, young leaves curl, fruits become deformed, and the whole plant may even die.
(6) Galls
The roots, stems, leaves and other parts of the plant form galls due to the attack or egg-laying stimulation of certain pests, affecting the ornamental effect.
2. Non-feeding damage
On flowering trees and shrubs this type of damage often appears in two forms: egg-laying damage and soil-burrowing damage.
(1) Egg-laying damage
Adults of the green leafhopper lay eggs in rows in the tissue beneath the epidermis of stems and branches, destroying the vascular tissue of the plants and causing branches and young trees to wither; the image shows eggs on a leaf.
(2) Soil-burrowing damage
Mole crickets burrow through the soil forming many tunnels, causing seedling roots to separate from the soil and die of dehydration, resulting in large numbers of missing and dead seedlings.
3. Transmission of plant diseases
Many plant viruses are transmitted by pests. The wounds caused by pest damage open entry points for certain pathogenic bacteria. In addition, the honeydew excreted by pests such as aphids, whiteflies and scale insects contaminates the leaves and easily leads to sooty mold, etc.
The above is the Huinong Network editor's summary of the harm pests cause to flowers. Flower lovers must raise their awareness of control and, when facing pests, control them early!
Control of the main flower pests
1. Aphids. Aphids, also known as sticky insects, occur in all four seasons and generally reproduce fastest at around 29°C. They mostly gather on the buds, young leaves or tender branches of plants, endlessly sucking sap and harming the bud core and petals. Control methods: 1. Take 50 g of fresh chili peppers or dried red chili peppers, add 300-500 g of water, boil for about half an hour, and spray the filtrate on the affected plants for a particularly effective result. 2. Take 3-4 g of laundry detergent, add 100 g of water, stir into a solution, and spray continuously 2-3 times; the control effect reaches 100%. 3. Add water to “fengyoujing” (essential balm) to make a 600-800 times solution, and use a sprayer to spray the pests carefully so that their bodies are covered with the medicated liquid.
2. Red spider mites. Red spider mites, also called short-whiskered mites, are pests that specifically harm the leaves and flowers of ornamental plants. Wild elm, Japanese bush cherry, five-needle pine and others in bonsai are also easily damaged by red spider mites.
The body of the red spider mite is about the size of a needle tip, dark red or purplish red; with the naked eye only a small red dot is visible, and only under a magnifying glass can the orange-red transparent spherical eggs be seen. Its larvae often gather on the undersides of leaves and on seedlings of some ornamental plants, piercing and sucking sap with their piercing-sucking mouthparts to harm the plant. Early symptoms are loss of green color in the leaves, leaf margins curling upward, then scorching and falling off, causing early shriveling of flower buds and, in severe cases, plant death.
Red spider mites produce 7-8 generations a year, begin to cause damage from March to April each year, and cause severe damage from June to July. After the end of April, plants should be inspected frequently; under conditions of high temperature, high humidity and poor ventilation, red spider mites reproduce extremely fast, which is one of the important causes of plant death. Control methods: 1. Soak citrus peel in about 10 times its amount of water for 1 day and night, filter, and spray the plants; this can control aphids and red spider mites, and if used to water flowers it can control nematodes in the soil. 2. Mix 15 g of laundry detergent, 15 ml of 20% caustic soda and 7.5 kg of water, spray after mixing well, and check after 1-2 days: the mortality rate of adult and young red spider mites is 94%-98%. 3. Light 1 mosquito coil, place it in the pot of the diseased plant, then tie the whole pot tightly in a plastic bag; after about 1 hour of fumigation, both eggs and adults can be killed.
3. Scale insects. The body of the scale insect is wrapped in a layer of horny shell, so spraying chemicals directly on it is not very effective. Like blood-sucking lice, they suck the sap of the plant, causing great harm to flowering trees and shrubs; affected plants not only grow poorly but also show yellowing leaves and early leaf drop. Control methods: 1. Mix baijiu with water at a ratio of 1:2, and when treating the insects pour it through the surface layer of the potting soil. Scale insects begin activity in spring when the room temperature is 7°C, so it can be poured once in mid-April, then about once every half a month, and results are seen after 4 consecutive times. 2. Take 50 ml of edible vinegar (rice vinegar), dip a small cotton ball in the vinegar until wet, and gently wipe the stems and leaves of the affected plants with the wet cotton ball to wipe away and kill the scale insects. This method is convenient and safe, and not only achieves the goal of removing the insects but also allows the affected leaves to turn green again. 3. Gently wipe the diseased plant repeatedly with alcohol to remove the scale insects.
Methods for group control of the main pests of garden flowers
1. Soil pests (also called underground or root pests):The soil used for flower cultivation is generally rich in organic matter, loose in texture, and good in aeration and water-holding capacity. The ecological conditions of these soils are also most suitable for the survival and reproduction of soil pests. For example, flowers such as narcissus, lilies, freesia, dahlias and cyclamen are often harmed by root mites, nematodes and springtails; and carnations, chrysanthemums and annual and biennial herbaceous flowers are often harmed by white grubs, mole crickets and cutworms.
Control methods:In addition to paying attention to soil hygiene and carrying out soil disinfection.
You can choose:
① 7051 insecticidal agent (avermectins):A 2000-3000 times solution, sprayed on the soil, is effective against root mites, nematodes and many soil pests.
② Diazinon (diazinon):A 500-1000 times solution, sprayed on the soil, has good control effects on harmful mites and insect pests.
③ Metolcarb:A 500-1000 times solution has control efficacy against woodlice and many other soil pests.
④ Miral 3G 3% granules:Can be applied into the soil or broadcast on the root zone of lawn grass; highly effective against mole crickets and white grubs, with a special effect on killing nematodes; broad insecticidal spectrum and systemic action, mostly used to control lawn pests, of relatively low toxicity, and can replace carbofuran (furadan) and aldicarb agents.
⑤ Phoxim 50% emulsifiable concentrate:Add water to make 1000-1500 times, and pour it around the root zone of affected plants; for example, for a 23 cm pot (7-inch pot), 100-200 ml each time, it can effectively control damage by white grubs and cutworms.
⑥ Tea seed cake water:1 part tea seed cake powder to 15 parts water, soak for two days and nights, filter out the cake residue, and pour it on; it is very effective against many soil pests, including earthworms. Fry wheat bran until cooked, then dissolve trichlorfon in a small amount of hot water, mix it with the wheat bran, with moderate dryness and wetness, so that when squeezed by hand (wearing rubber gloves) no water seeps out between the fingers, and when the hand is released it can be scattered on the soil surface around the roots; this is very effective against cutworms and mole crickets.
2. Greenhouse pests:The ecological conditions of a greenhouse are rather special: high temperature, small temperature difference, high humidity, little air movement, abundant food and few natural enemies; therefore pests reproduce quickly and the damage period is long. The common and more seriously damaging pests in greenhouses include: scale insects, aphids, spider mites, woodlice, millipedes, cone snails, slugs and snails. Control methods:
① Derris extract:It is a commonly used agent for controlling aphids; generally diluted 1000-2000 times, it has good results.
② 40% omethoate:It has good systemic and translaminar properties; diluted 1500-2000 times, it is effective against aphids, scale insects and spider mites.
③ 40% acephate:Low toxicity; add water to make a 1000-1500 times solution, with good control effect on aphids; if mixed with carbaryl powder it can also control thrips and has an obvious synergistic effect.
④ Fenitrothion:It is effective against mosquitoes, aphids and spider mites. For bulbs carrying root mites, it can be diluted 1000 times, soaked for 30 minutes, then air-dried for storage, which can control damage and reproduction throughout the storage period; it is phytotoxic to pomegranate.
⑤ Para-dichlorobenzene:Place dry bulbs carrying root mites in an airtight container or plastic bag, and fumigate with a dose of 4 g/L for 1-2 days to kill all living bodies.
⑥ 20% fenvalerate:Diluted 2000 times, it has a special effect of quickly knocking down woodlice.
3. Piercing-sucking pests:Among flower pests, piercing-sucking pests are an important group, mainly including: mosquitoes, aphids, spider mites, thrips, whiteflies and leafhoppers.
Control methods:
① Use Phytoseiulus persimilis to control two-spotted spider mites:In the greenhouse, beneficial mites can be released at a ratio of 1:20-30 of beneficial to harmful mites, and after 7-14 days the damage of two-spotted spider mites can be completely controlled……
② 73% propargite emulsifiable concentrate:It can kill adult mites, young mites and eggs. It is harmless to beneficial mites and other natural enemies; generally use a 1000-3000 times solution, with an efficacy period of 14-35 days.
③ 5% hexythiazox emulsifiable concentrate:It is a low-toxicity acaricide, safe to natural enemies, with very low toxicity to bees and birds, for example. It has a strong young-mite-killing property against many plant harmful mites; its control effect on adult mites, rust mites and eriophyid mites is relatively poor. For general spider mites use a 1500-2000 times solution.
④ Petroleum emulsion:It is a mineral-source pesticide, effective against all the "five small" pests, and has unique advantages when applied at scenic spots and orchards.
⑤ Dicofol:It is effective against spider mites and root mites; if mixed with tetradifon, it has a long-term control effect on mites. For root mites, diluting 1000-1500 times also gives good results.
⑥ Pyridazinone (15% emulsifiable concentrate):It is a high-efficiency, low-toxicity, broad-spectrum acaricide and insecticide, with good control effects on piercing-sucking pests such as whiteflies, leafhoppers, thrips and aphids, and very high activity against both adult and young mites; use at 2000-3000 times dilution.
⑦ Imidacloprid:Also known as Bilin, it is a 12.5% imidacloprid water-soluble concentrate, a high-efficiency, strongly systemic, broad-spectrum insecticide, with a special effect on piercing-sucking pests such as aphids, planthoppers, psyllids, thrips and scale insects, and it is excellent for controlling the bamboo stem flat aphid.
4. Leaf-eating pests:Mainly including most lepidopteran larvae, and some adults and larvae of Orthoptera and Coleoptera, etc.
Control methods:
① Biological agents:Bt (Bacillus thuringiensis) emulsion, Beauveria bassiana preparations, nuclear polyhedrosis virus (NPV) preparations, cytoplasmic polyhedrosis virus (CPV) preparations, and interfering virus preparations, etc. 7051 insecticidal agent: it is avermectin, also a biological agent, with very high activity.
② Hormone preparations (specific pesticides):
Specifically the following:
Diflubenzuron No. 3:It inhibits insect molting and can also inhibit the embryonic development of pest eggs; it is effective against many lepidopteran larvae, has already been mass-produced and widely promoted and applied; it is non-toxic and does not affect the ecological environment; its 25% suspension concentrate can be diluted 3000-4000 times. Yitaibao (5% emulsifiable concentrate): also a new type of insecticide that hinders insect molting, with functions and characteristics similar to diflubenzuron. When applied it can be diluted 2000-4000 times, with higher activity.
Miman (20% suspension concentrate):It is a hormone agent that accelerates insect molting, can prompt pests to molt prematurely and age before growing old, and is effective against various instars of many lepidopteran larvae; the use concentration is diluted 1000-2000 times.
③ Plant-source preparations:For example, Sushawei, a 5% toosendanin and nicotine liquid, is a purely natural ingredient, effective against many pests and mites, and has a very notable effect in controlling the box tree pyralid (Diaphania perspectalis).
④ High-efficiency, micro-toxic or basically non-toxic chemical agents:
Specifically the following:
1. Duolaibao:This is an insecticide synthesized from only three elements, carbon, hydrogen and oxygen (C25H28O3), and has very high insecticidal activity against many leaf-eating pests.
2. Lorsban (also known as chlorpyrifos, lorsban):Low toxicity, no systemic action. It can control leaf-eating pests and mites, and has good effects on beet armyworm, tobacco cutworm, cutworms and others that are active and damaging around the roots or that cocoon and pupate there.
3. Phoxim:Low toxicity, broad insecticidal spectrum and strong knockdown power; effective against many lepidopteran leaf-eating pests, and also has a certain killing effect on insect eggs.
4. Fenitrothion:It has a special effect on controlling leaf-eating pests such as Atractomorpha sinensis and scarab beetles.
5. Leaf-mining and gall-causing pests:Leaf-mining moths on Rutaceae plants, leafminer flies on Asteraceae, and gall aphids, gall mites and tarsonemid mites on many flowers are causing increasingly widespread damage.
Control methods:Apply permethrin, which has a special effect on leaf-mining pests (effective ingredient 15×10-6); 40% omethoate is also very effective; foliar spraying with dicofol and 7051 insecticidal agent also has good effects on gall mites. Lorsban has a notable effect in controlling leafminer flies.
6. Borer pests:Those damaging flowers and ornamental plants include: the four-yellow-spotted jewel beetle, the chrysanthemum longhorn beetle, the pine shoot borer, the cotton bollworm, the tobacco budworm, the tobacco cutworm and the Euonymus glabrous longhorn beetle, etc.
Control methods:Apply agents with good systemic action and strong contact-killing power, such as aluminum phosphide, fumigation sticks, sulfuryl fluoride and fenitrothion; use Yitaibao to control noctuid larvae damaging flower buds, with obvious results.