Pest and Disease Management in Kiwi: Causes, Symptoms, Treatment, Chemical, and Biological Control

Known for its edible fruits, Kiwi is a deciduous climbing vine or shrub in the family Actinidiaceae. This plant is vigorous and woody, with nearly circular leaves and long petioles alternately arranged on the stems. It has red hairs on the young leaves, while mature leaves have smooth, dark green tops and white, downy bottoms. At the leaf axils (area between the leaf and stem), the kiwi plant produces fragrant white-yellow flowers that are borne singly or in three clusters. Green-brown skin covered with stiff brown hair covers the oval fruit.

Many tiny black seeds are embedded in its flesh, which is bright green and juicy. The fruit production of kiwi plants declines after three years when they reach a height of nine meters. It originates from China and is also known as kiwifruit or Chinese gooseberry. Himachal Pradesh, Uttar Pradesh, J & K, Sikkim, Meghalaya, Arunachal Pradesh, and Kerala are the states where Kiwi is most commonly grown. Kiwi plants are tough and relatively easy to grow, but they are susceptible to various diseases. Kiwi farming is affected by the following diseases and pests.

Pest and disease management in Kiwi

Major pests in kiwi fruit

Leafrollers

One of the most common and damaging leaf-rolling caterpillars is the omnivorous leafroller. The omnivorous leafroller caterpillar’s body color ranges from cream to brown, and its head capsules range from light brown to black. Furthermore, omnivorous leafroller moths may develop on plants outside and infest vineyards. Depending on the climatic conditions, omnivorous leafrollers have four to six generations per year.

Fruit tree leafrollers, oblique banded leafrollers, and orange tortrix may also attack kiwifruit. It only reproduces once a year and is a minor pest of kiwifruit trees. Larvae feed on leaves until about June after hatching from overwintering eggs. Caterpillar larvae are dark green with blackheads. In June or July, adult moths appear and lay overwintering eggs.

Damage symptoms

It feeds on leaves by curling them up and sticking them together with silk webbing to make a shelter to feed in.
When a caterpillar reaches maturity, it starts eating through the leaf rather than feeding on the inner surfaces. Host plants can suffer serious damage as a result of this damage.
A leaf-rolling caterpillar, such as omnivorous leafroller, damages fruit directly by scaring the fruit’s surface when it feeds.

Biological Control

Various parasitic wasps and tachinid fly attack leafroller eggs, larvae, or pupae.
Natural enemies of green-headed leaf roller like Predatory mites, Predatory Wasps
Larval parasitoids like Trigonospila brevifacies, Braconid wasp, Dolichogenidea Tasmania, and Goniozus jacintae will have better control of these pests.

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Chemical control

At the end of the hatch, apply Bacillus Thuringiensis Ssp Kurstaki. At low rates, it is most effective on small caterpillars. You may need to repeat the application in 5 to 10 days, or you may need to use a higher rate for large larvae.
Cryolite can only be applied on the ground with a spray rate of up to 200 gallons per acre. Therefore, a maximum of four applications per season should be made at intervals of 15 to 30 days.
When severe damage occurs, use Esfenvalerate. The product is only effective when the temperature is above 23°C. The number of applications should not exceed seven per season, and the interval between sprays should not be less than seven days.

2. Armored Scales

Scale insects infest the leaves, cordons, canes, and fruit of kiwifruit vines. The greedy and latania scales are armored and similar in size to the adult oleander scale. However, the waxy shell covering these two species is more conical, with a small black spot or nipple to one side of the center.

If the shell is removed, the female body is yellow. The adult female oleander scale is an armored scale that is about 0.1 inches (2.5 mm) long and oval. It has a waxy covering with a yellow or light brown spot near the center. The adult male scale is elongated. If the coverings are removed, the female body is yellow, while the male scale is brownish yellow. There are several generations a year.

Damage

Scale insects feed on plant fluids and can be located on the bark or fruit of kiwis. Heavy infestations affect the plant’s vigor and result in scales on fruit, causing it to be off-graded.
Heavy infestations affect the vigor of the plant and result in the presence of scales on fruit, causing it to be of grade

Biological control

Various predatory insects and parasitic wasps kill armored scales. Parasites include species of Aphytis wasps, and predators include green lacewings, brown lacewings, minute pirate bugs, and small species of lady beetles.
Double-sided sticky tape wrapped around vine cordons determines when crawlers are present. Therefore, monitoring scale crawler populations is beneficial in determining the efficacy of the delayed-dormant treatment.

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Chemical control

Apply narrow-range oil to control these pests
Apply Pyriproxyfen and Use it for higher rates for high numbers of scales.
Evidence of scale on canes during dormant pruning or off-grade fruit at harvest caused by the presence of scales is justification for treatment.
Treatments are applied during the dormant period after pruning and tying to permit better spray coverage before bud break to avoid phytotoxicity.

Two-spotted spider mite

Most of them are attached to silk webbing. T urticae mites lay 10-20 eggs per day, 80-120 eggs altogether during their lifetime of up to 4 weeks. After 3-15 days, the six-legged larvae hatch. A protonymph molts three times within 4-5 days, followed by a deutonymph molt, and finally, an adult molt.

These instars all have eight legs. Before each molt, there is a short quiescent stage. In favorable conditions, the life cycle can be completed in about 1-2 weeks, including a pre-oviposition period of 1-2 days. A change towards hot and dry weather often leads to a rapid increase in population density.

Damage symptoms

Your plant’s leaves have patterns of light-colored dots or stippling
Sometimes, but not always, tiny holes where the spider mites have chewed straight through.
More advanced damage may cause leaves to turn yellow or red, die suddenly, and prematurely drop off your plant.
Perhaps the most infamous telltale sign of spider mites is the delicate webbing found beneath leaves and in the joints between leaf and stem. This webbing is so fine and delicate

Biological control

Alternatively, for a one-time application treatment, you can employ the natural predators of spider mites, such as predatory mites, ladybugs, and lacewings, to hunt out and take care of any remaining spider mites.
Predators of two-spotted spider mites are Phytoseiulus persimilis, Stethorus punctillum

Chemical control

Neem oil is an effective treatment and preventative measure for several common houseplant pests. However, its effectiveness is cumulative, so it must be regularly re-applied before it reaches its full potential.
Cinnamite is a pesticide derived from cinnamon oil and is non-hazardous. It won’t kill eggs but will effectively kill adult spider mites. For maximum effectiveness, spray your plant every three days over a couple of weeks to ensure you get all the newly hatched spider mites before they start laying their eggs.
Bifenazated does not make more than one application per harvested crop. Two sprays may be made annually if more than one crop is harvested each year; the minimum period between applications is 21 days.

Thrips

Elongated and white, banana-shaped eggs are produced by the species. Eggs are inserted inside plant tissues above the soil surface by females. When the larva is whitish with red eyes, it turns yellowish with maturity but retains its red eyes. Pupae and pre-pupae are white to slightly yellow. Larvae resemble adults but lack wings, and adults measure 1.3 to 1.7 mm long. An adult’s abdomen is golden when it first emerges.

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Damage symptoms

The mouthparts of thrips are used to rasp the leaf surface, rupture epidermal cells, and feed on exuding cell contents.
As soon as an infestation occurs, growth and flower production is stunted, and fruit sets are delayed.
The feeding spots turn yellow, then brown, and the surrounding cells become silvery when the air enters
Infected leaves become crinkly and curl upward.

Biological control

Natural enemies of thrips are
Larval parasitoids: Thripobius semiluteus
Predators: Predatory mites, predatory thrips, hoverflies, mirid bugs, etc.
Naturally occurring minute pirate bugs (Orius spp.) feed on thrips. Orius are also available commercially, but release rates and timing have not been determined.

Chemical control

After two successive applications of Spinosad, rotate to an insecticide with a different mechanism of action.
Apply Malathion, which has a one-week residual effect. Bees are highly toxic to this chemical; do not spray directly on blooming crops or weeds where they forage.
Apply carbaryl for the best result

Root-knot Nematode

As part of their life cycle, plant parasitic nematodes produce eggs, larvae, and adults. The first molt occurs in the egg during the larvae’s first development stage. The larvae hatch from second-stage eggs and infect plants’ roots or foliar tissues. It takes 4 to 8 weeks for new larvae to emerge and complete the life cycle under suitable environmental conditions. Generally, nematodes develop most rapidly at 21 to 26°C, the optimal soil temperature range.

Damage symptoms

A primary symptom is the formation of galls on the root systems of the host
A ‘beard root’ symptom is caused by roots branching starting from the gall tissue
Knobby and knotty roots are a sign of infection
Infected plants have reduced root systems and almost no rootlets. Roots seriously hinder water and nutrient uptake and transport
It is common for plants to wilt in the heat of the day, especially in dry conditions, and to become stunted

Chemical control

The application rate for Telone II cannot exceed 35 gallons per acre of 1,3-dichloropropene. Apply methyl bromide to dry soils with slight surface moisture.
Suppose you do not have old root systems containing viable root-knot nematodes. In that case, Metam sodium, applied at a rate of 75 gal/acre in 6 inches water/acre, can be as effective.

Diseases in Kiwi farming

Bleeding canker

Bleeding canker is characterized by rusty cankers on branches that produce an unsightly reddish discharge. Kiwifruit stem is usually pruned about 12 inches (30 cm) from bleeding canker-affected areas in most areas where kiwifruit are grown. In most kiwifruit growing areas, bleeding canker has been observed. Pseudomonas syringae overwinters on kiwifruit vines, weeds, and grasses in vineyards.

Damage symptoms

Bleeding canker symptoms appear soon after leaf emergence in early spring. In young canes, “hooking” is evident at the terminal growing point, as well as leaf wilt, blight, and canker formation.
A dried, shriveled bark is one of the external symptoms of cane disease. In addition, red-rusty brown discoloration occurs internally in affected tissues.
The canker is often associated with a pruning wound. A canker may develop on a cane, cordon, or trunk. When trunks are attacked, plants are often killed beyond the bud union.
The growth of less severely affected plants generally resumes in late spring. The canker margins produce profuse rusty red exudate (bleeding), often resulting in discolored bark tissue.
In severely affected plants, rootstock suckering is extensive.

Chemical control and Management

Copper bactericides are recommended to treat bacterial cankers effectively.
Adding ferric chloride or mancozeb to cupric hydroxide provides good control of the strains that develop resistance over the years.
Prune infected vines when symptoms are observed. Make cuts one foot below the leading edge of the canker.

Bacterial leaf blight

Pseudomonas viridiflava and Pseudomonas syringae are widespread plant pathogens on the leaf surfaces of many fruit and vegetable crops. Rainfall favors the growth of bacteria. They gain entry into a plant through injured tissues or when it has been predisposed to disease by conditions such as chilling injury. Symptoms in kiwi fruit include angular spots often associated with a halo. In advanced stages of infection, black-rusty gum leaks from some leaf spots, but not all. Furthermore, not all symptoms appear at the same time.

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Damage symptoms

Bacterial blight symptoms appear as brown, sunken lesions on the petals that enclose the floral buds.
During bud expansion, the petals exhibit a yellow-orange discoloration that becomes necrotic.
The buds fail to mature and abscise. Small yellow leaf spots may occur after summer rains or when overhead irrigation is used.
The major symptoms include leaves with undulated yellowish white or golden yellow marginal necrosis, drying leaves back from tip and curling, and leaving mid rib intact.

Chemical control and Management

Currently, there are no recommended chemical control strategies for the disease. Rather, it is controlled by avoiding injuries to the plant that allow bacteria to enter.

Armillaria Root Rot

The fungal pathogen survives on diseased wood and roots for many years. When land is cleared and ready for planting kiwi vines, roots from preceding orchard crops, nearby oak trees, or remnants of Armillaria-infected roots can infect healthy plant roots. However, kiwifruit plants somewhat tolerate this fungus if the vine has already been weakened by Phytophthora infection.

Flood waters sometimes spread infected roots in a vineyard. The fungus is favored by continually damp soil. Although the pathogen may produce mushrooms around the base of the vine trunk, they are not considered significant in disease spread.

Damage symptoms

Vines infected with Armillaria root rot usually completely collapse.
Occasionally, white mycelial mats can be found under the bark at the soil line, but more commonly, white mycelial strands are seen interwoven through darkened cortical tissue.
In addition, dark, rootlike structures called rhizomorphs grow from the root into the soil after symptoms develop on vines.

Chemical control and Management

When clearing land for planting or replanting vines, carefully remove and burn roots 1 inch or greater in diameter. Ensure that vines are properly irrigated and not overwatered.
Soil fumigation with carbon disulfide may ensure the absence of Armillaria mellea in an orchard before planting the young trees.
The application of the products can also be carried out by irrigation but never by spraying. Irrigate the feet early in the attack when the vegetation is yellowing with products containing Fosetyl aluminum, metalaxyl, or Thiophanate-methyl fungicides.
Agricultural tools should be disinfected with bleach after use to prevent the spread of the disease,

Botrytis Fruit Rot

During fruit maturation and ripening in storage, the infection may begin at bloom. As the fruit ripens, the pathogen can resume growth, usually in cold storage, and cause postharvest rot. Most infections occur at the stem end, where the stem is snapped off during harvest or on the surface during harvest and handling. Fruit sepals and stems may also be infected. Rainy weather during bloom or especially at harvest makes this disease more severe.

Damage symptoms

A soft fruit rot called botrytis fruit rot can result in significant crop losses during storage.
Decay symptoms include shriveled fruit with gray fungal growth around the stem end and sometimes around the sepals or the entire fruit surface.
The internal fruit tissues of diseased fruits appear dark green and water-soaked.
The fungus’s black, irregularly shaped sclerotia may appear on fruits infected with the disease.

Chemical control

Apply Captan Can be tank mixed with Fenhexamid (Elevate), thiram, or Thiophanate-methyl (Topsin-M) for more effective control.
Application of Cyprodinil may be made by ground. One to two applications began 14 days before harvest, on a seven to the ten-day interval before harvest.
Use Fludioxonil as a postharvest dip or spray. The dilution rate depends on the application method to ensure the application of the fungicide to the stem end wound. Do not make more than one application

Phytophthora Root and Crown Rot

In irrigation water from surface sources, the pathogens survive in soil and can be carried by the water. Therefore, it is optimal for the pathogen to infect roots during prolonged periods of saturated soil. Disease development is enhanced in poorly drained soils or vineyards receiving long durations of flood irrigation. Several species of Phytophthora attack kiwifruit roots and crowns.

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Damage symptoms

A chlorotic, undersized leaf and an open canopy are common symptoms of Phytophthora root and crown rot.
The vines may collapse suddenly or decline slowly over a few seasons as the temperatures increase in summer.
Infected vine roots and crowns exhibit a reddish-brown rot that can be observed by cutting into the cortical tissue. Diseased tissue often appears at a margin where healthy tissue meets white tissue.
Active lesions often progress above ground on one or more sides of the lower trunk, leading to sunken areas.

Chemical control management

Plant on raised berms in well-drained soil to allow for rapid water drainage following irrigation or rains. The duration of irrigations should not exceed six hours in fields where the disease occurs. Intervals between irrigations may be shortened as long as the soil drains adequately since the last irrigation.
If the product is injected or incorporated into the soil, Mefenoxam is not required to be applied, and workers won’t come into contact with treated materials.
Apply Phosphonates Foliar, and chemigation applications are labeled.

Conclusion

Pests and diseases require different fungicide application strategies. A schedule can be used to apply fungicides rather than making observations in the vineyard when minimal risk is desired. Several factors determine whether fungicides should be sprayed, including weather conditions, vine stage, Kiwi variety, and parasitic pressure.

1 COMMENT

Ashish Kumar July 24, 2023 At 1:07 pm

It’s a nice article with complete information provided. I have been facing the following issue: my kiwi leaves are falling down on a daily basis but fruits are safe on kiwi vines. With the help of this article, I found that my kiwi vines are attacked by spider mites for which I can use neem oil.

Pest and Disease Management in Kiwi: Causes, Symptoms, Treatment, Chemical, and Biological Control

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