Common pests of canna and their control methods

Canna

Canna is a kind of plant that does not have high requirements for living environment, easy to breed, easy to reproduce and has a long flowering period. It is a common green plant on the roadside, and it is a plant that beautifies the environment in many courtyards. Generally speaking, as long as there is plenty of sunshine and water, it can be fed anywhere. However, no matter where the canna grows, it can not avoid being disturbed by pests, so what are the common pests and diseases of canna?

1. Mosaic disease

Symptom

The leaves of the susceptible plants showed flower leaves or yellow-green spots, and the petals became smaller and formed variegated colors. When the disease was serious, the leaves became deformed, involuted and plaque necrotic.

Prevention and cure method

1. Because canna propagates in separate roots, it is easy to spread the virus year after year, so it is appropriate to choose virus-free mother strains as breeding materials. Diseased plants were immediately removed and destroyed in order to reduce the source of infection.

two。 The disease is transmitted by aphids. Insecticides are used to control aphids and reduce disease vectors. Spray with 2000 times of 40% omethoate or 1000 times of 50% malathion, 20% diazinon and 70% aphid.

Second, whitefly

A pest of the family Homoptera, having a small body and white powdery wax all over the body, usually harming plants in clusters. It is easy to occur when the cultivation is poorly ventilated. It often harms the young leaves and buds of canna, which is inserted from the back of the leaves with a prick aspirator to absorb the juice from the plant tissue, make the leaves withered and yellow, and often excrete a large amount of honeydew in the wound, causing coal pollution, mold and other diseases. Because of its strong fecundity, whitefly can reproduce 910 generations a year in the greenhouse, which can form a large number in a short time.

Prevention and cure method

Due to the white waxy powder on the body of the adult whitefly, which brings difficulties to the control, the control should be timely, and the drug control should be better in the nymph stage. 2.5% deltamethrin, or 10% permethrin, or 20% dimethrin diluted 2000 times, the effect is better; or 40% dimethoate, or 80% dichlorvos, or 50% marathon emulsion should be sprayed for 2 times every 5 to 6 days. Can also be used pest natural enemies such as aphids wasps, but also have a certain effect.

3. Bud rot

Symptom

Before the leaf development and flowering of the banana, the bud rot bacteria invaded through the stomata of the young leaves and flower buds. During the leaf development, many small disease spots appeared on the leaves, and gradually expanded, connecting with each other along the leaf veins to form large spots, and sometimes the disease spots formed stripes. The plaque is grayish white at first and soon turns black. The infected flower buds blacken and die before flowering. The disease spot can expand downward along the petiole, causing the death of young stems and buds. When the old leaf is damaged, the disease spot expands slowly, the shape is irregular, yellow, and the edge is watery.

Prevention and cure method

1. The healthy rhizome was selected as the propagation material, and the suspected bacterial rhizome was soaked in 500-1000 times solution of streptomycin for 30 minutes before planting, which could not only prevent the disease, but also promote the growth of buds and branches.

two。 Should be planted in sunny, fertile, moist, well-drained areas to avoid planting too dense.

3. The plant was sprayed with Bordeaux solution (1) or 77% of the wettable powder 500 times, 14% ammonia copper solution 400 times, and so on.

4. Remove seriously diseased plants and remnants at any time and burn them.

Canna

4. Banana bract worm

The adults of banana bracts lay their eggs on the leaves, tender stems and petioles of canna plantain. After hatching, the larvae climb to the leaf edge and bite the leaves, and the leaves are spun and glued into curls. Sooner or later, they climb out of the bracts and bite the nearby leaves. In serious cases, there are numerous leaf bracts and incomplete leaves on the plant, affecting the growth and ornamental effect.

Prevention and cure method

Remove the leaf bud and kill the larva in time

Before the larvae hatch, kill the larvae with 1000 times of trichlorfon, or spray them with 1000 times of Yitaibao in the morning or evening.

Fifth, Little Land Tiger

Small land tiger, also known as ground silkworm, black soil silkworm, etc., is the larva of moths, with a yellowish brown to dark brown body, obvious topline and rough epidermis, and can reproduce for 4 or 5 generations a year. Its adult is a medium-sized moth with brown forewings, kidney-shaped lines and black wedge-shaped spots, which is obvious. In the event of damage, wormholes will be seen in the leaves of the plant, which will seriously damage the flower bud and lead to the production of non-flowering plants.

Prevention and cure method

In the process of cultivation and management, remove the surrounding weeds and keep the environment clean. The adults can be killed by black light or sweet and sour, and the larvae can be killed by stacking grass or poison bait. If you stir with 90% crystal trichlorfon and wheat bran or bean cake crumbs at 1:50, sprinkle it on the rhizosphere in the evening. It can also be poured on the rhizosphere or seedling bed with 50% phoxim, 40% dimethoate, or 1000 times of dichlorvos to kill small tigers.

No matter farmed animals or plants, farmers are most worried about diseases. Common diseases can be treated as long as the causes are found and drugs are found, but infectious diseases are beyond the control of farmers, so prevention is crucial.

Insect pests and control methods of canna

The insect pest of canna: curly leaf worm

Symptom

In summer and autumn, the larvae spit silk and adorn the leaves into rolled leaves or folded leaves, in which the larvae hide the mesophyll, residual veins and upper epidermis, forming a transparent grayish brown film, which is called "open skylight".

Although canna has strong adaptability, it is necessary to pay attention to the damage of leaf curlers to canna from May to August every year, so as not to damage young leaves and inflorescences.

Prevention and cure method

Kill the overwintering larvae near fallen leaves, cracks or buildings in autumn and winter, kill the newly hatched larvae in summer, and remove the injured leaves if necessary.

It can be sprayed with 50% dichlorvos 800 times or 50% prednisone EC 1000 times.

The insect pest of canna: Canna bract

Symptom

The adults of the banana bract will lay their eggs on the leaves, tender stems and petioles of the canna, wait for the larvae to hatch, and then climb to the leaf edge to bite the leaves, and the banana bracts will spin and glue the leaves into curly bracts, climbing out of the curly bracts in the morning and evening. Bite the nearby leaves.

Plants seriously eroded by banana bracts will appear a large number of leaf bracts and incomplete leaves, which seriously affect the growth and ornamental effect of canna.

Prevention and cure method

When the leaves eroded by banana bracts are found, the leaf buds should be removed in time and the larvae should be killed.

Before the larvae hatch, kill the larvae with 1000 times of trichlorfon, or spray them with 1000 times of Yitaibao in the morning or evening.

The insect pest of canna: ground tiger

Symptom

Ground tiger, polyphagous pest. The canna is mainly harmed by the larvae, which bites off the stem of the seedling near the ground, resulting in the death of the whole plant.

Prevention and cure method

When it is found that the ground tiger harms the canna plant, it can be caught manually, or the root soil can be infused and controlled with 600Mel 800 times of trichlorfon.

Control of drilling pests in August the main pests harmful to flower seedlings are longicorn beetles, Dahlia borer moths, rose stem wasps, gibberries and other pests, and most of them have laid eggs and hatched before August, so August is a key period for their harm. it's also a key period for prevention and control. The details are as follows:

I. harmful symptoms and main characteristics of borer pests

The main harmful symptoms of longicorn beetles are that the larvae harm the phloem and xylem of the host. The newly hatched larvae decay vertically from the phloem into the sapwood, eat laterally and inwardly along the spring wood part of the outermost ring of the branch. The decay path is in the shape of "Z". Adults feed on the tender skin of new shoots to replenish nutrition, and the edges of the eaten parts are neat, and they are not good at flying, so they are easy to fall to the ground when shocked. Lay eggs in places such as cracks in the bark, and then cover the eggs with grass-green secretions. (pictures of the main features and hazards of longicorn beetles).

The harmful symptoms of the insect: the larvae eat vertically and horizontally between the cambium and xylem, destroying the transport tissue, causing the tree to weaken and the trunk to die gradually, resulting in the death of the whole tree. In general, the management is extensive, the tree is weak, the tree with many wounds is seriously injured, and the tree is strong and injured lightly. (picture of the giddy bug)

The harmful symptoms of Dahlia borer moth are that the larvae eat the stems of garden flower plants such as dahlia, chrysanthemum, green poplar, canna, gladiolus, palm, hemp and so on. When the damage is serious, all the stems are almost damaged by decay and cannot blossom. The stem of the injured plant is easy to break and can not bloom, and the upper part of the stem is withered and yellow and dies. (picture of Dahlia borer moth)

The harmful symptom of rose stem wasp is that the larvae eat the stem of flowers and often fold and wilt from the wormhole, which is very harmful to rose. (picture of Rose Stem Bee)

2. Control measures of borer pests

(1) Prevention and control measures in August:

The main results are as follows: 1. pay attention to the inspection, it is found that the branches of flowers and trees harmed by Dahlia borer moth and rose stem wasps should be cut off in time and burn and kill the larvae; longicorn beetles and gibberries mainly harm the trunk of trees, and the larvae are still eating under the cortex of the root and neck, or when the xylem is not deep, hook killing is carried out in time.

2. Chemicals can be used to kill larvae when the larvae drill deep into the xylem.

80% dichlorvos, 40% omethoate or 50% phoxim are injected into the wormhole, and then sealed with poison mud, which can kill the larvae.

Insert a poison stick into the wormhole to kill the larva (the poison label can be made with zinc phosphide, peach gum, oxalic acid and bamboo stick).

In the initial stage of larval damage, 5% permethrin or 50% methamidophos EC 5% 10 times, or 80% dichlorvos EC 5 times, or 1:20 dichlorvos kerosene solution can be used to brush the skin of the injured part (the affected area is slightly sunken and blackened) or tree trunks, the effect of killing larvae is very good.

(2) other prevention and control measures

1. Strengthen quarantine when transporting seedlings. The worm-carrying logs were fumigated with methyl bromide, thioyl fluoride or 56% aluminum phosphide tablets with the dosage of 20-30g/m3 and 12-15g/m3 for 24 hours and 72 hours respectively, or the pest wood was soaked in water for more than 1 month. after peeling the logs, the twigs were dipped in 20 times of fenvalerate EC or 40% omethoate EC or 2.5% deltamethrin EC and inserted into wormhole to kill pests.

2. Strengthen the management and strengthen the tree potential, scrape off the rough warped skin of the trunk and main branches and prune the insect branches during the dormant period. Eliminate some overwintering insect sources; timely remove dead trees and dead branches and burn them so as to reduce insect sources.

3. Artificial prevention and control

a. The peak of adult Eclosion is in late June, and the adult can be stabbed to death with a screwdriver before it bites the Eclosion hole and flies out. When the adult has just drilled out of the Eclosion hole, it crawls on the tree trunk and has gregariousness, so it can be caught directly at this time.

B. artificial killing of eggs and newly hatched larvae. The adult spawning period and hatching period are from late June to early July, and the first eggs are green and easy to identify; the larvae are in the outer layer of the bark at the initial stage of hatching, which is easy to remove, and the larvae can be artificially removed and killed at this time.

C. Prevention and treatment of egg induction: using woven bags such as packaging chemical fertilizers, after washing, they are cut into long strips 20-30 cm wide. Before Anoplophora alternatus spawn, 2-3 circles are wound with cut braided strips in the trunk where it is easy to lay eggs, leaving no gap between each circle, and then tied up with hemp rope, the control effect is very good. By bandaging and blocking, longicorn beetles can only put their eggs on a braided bag, and the acquired eggs will lose water and die.

4. Chemical control

b. In the peak period of the activity of the older larvae (from the end of March to the middle of April), in the future, 30 times of the solution of Fuling or dichlorvos or dimethophos or monocrotophos will be injected into the defecation hole or breathing hole with a needle, and then the hole can be sealed with yellow mud.

c. During the peak period of adult activity from the middle of June to the middle of July every year, 2000 times of permethrin was sprayed on the crown of the host tree, once every 15 days, twice continuously, and a good effect could be obtained.

d. Before overwintering (November and December), 10 kg of lime + 1 kg of sulfur + 10 g of salt + 20 kg to 40 kg of water were used to paint tree trunks to prevent spawning. (source: finishing by Yang Yanwei and Xie Xiaomin of China Lawn Network)