Bacterial Diseases

1- Crown Gall

The Causal organism:
Crown gall
          Bacterium – Agrobacterium tumefaciens:    Crown gall first appears as small round overgrowth on stems and roots. As they enlarge, the galls become woody with a rough and irregular surface. Aerial galls can develop but most are found at or just below the soil line. Galls range from pea-size to larger than 1 foot in diameter.

Crown gall is worldwide in occurrence, attacking 140plant genera in 60 different families. Plants most commonly damaged by crown gall are pecan, peach, blackberry, grape, apple, pear, and fig

Crown gall bacteria infect plants through wounds, such as those arising from cultivation, transplanting, wind damage, insect injury, etc Wounds that have healed beyond a certain point are no longer susceptible to invasion. After establishing it self in the wound, the bacterium transforms normal plant cells to tumor cells once this has taken place, the tumor cells are able to reproduce without the bacterium being present although crown gall of planets is very much like cancers in humans and other animals, there is no relationship between crown gall and animal cancers

Damage to infected plants results from interruption of water and nutrient movement up the stem galls also interfere with normal growth and development therefore, infected plants may be stunted and unthrifty. With many plants, the amount of damage depends on where the gall or galls are located and how many are present. Death can result if galls girdle the primary trunk or stem infected plants are more sensitive to winter injury and drought stress. Control is primarily dependent on prevention. Pruning off galls is not effective since the bacterium is systemic and gall tissue can reproduce itself. Chemical control with antibiotic drenches has shown promise however they are not practical at this time the following practices pertain to homeowners and /or nurserymen

Control
1- Inspect plants of crown gall before purchasing plant only crown gall- free trees and shrubs
2- Remove and destroy heavily infected and weakened plants out at the orchards
3- Replace with a more resistant type plant if possible
4-Avoid wounding plants while mowing, cultivating
5- Keep plants in an active growing state with proper fertility and watering.
6-Heavily infected nursery fields should be planted to a grass crop for three years before planting susceptible nursery stock.
7-Control root feeding insects.
8-Dip grafting and pruning tools regularly in a disinfecting solution

2- Fir bligh

Fire blight is a bacterial disease that affects certain species in the rose family. It is especially destructive to apple, pear, quince and crabapple.

Disease Cycle

Fire blight is caused by the bacterium Erwinia amylovora. The bacteria over winter in blighted branches and at the edge of cankers (areas of bark killed by bacteria) In spring, when temperatures reach 28-30C and frequent rain occurs, bacteria resume activity and multiply rapidly.

Masses of bacteria are forced through cracks and bark pores to the bark surface, where they form a sweet, gummy exudates called bacterial ooze. Insects such as bees, ants, flies, aphids and beetles are attracted to this ooze, pick up the bacteria on their bodies, and inadvertently carry the bacteria to opening blossoms. Bacterial ooze splashed by rain also can spread the pathogen

once in the blossom; bacteria multiply rapidly in the nectar and eventually enter the flower tissue. From the flower, the bacteria move into the branch. All flowers, leaves and fruit above the point of infection die.

Young branch tips can be infected through stomata (air openings on leaves), lenticels (air openings on branches), or, more commonly, through wounds created by pruning, Insects or hail storms. Droplets of ooze can form on these infected twigs within three days. Fruit may be infected through insect wounds. Girdling cankers eventually develop from branch or blossom infections.

Symptoms

Symptoms of blossom blight are first seen about the time of petal fall. Infected blossoms appear water-soaked and wilt rapidly before turning dark brown. Leaves wilt, darken and remain attached to the tree This gives the tree a fire-scorched appearance, thus the name "fire blight."

Infected twigs exude creamy bacterial ooze in droplets or fine, hair-like strands. Tips of twigs turn black and curl over when dry, causing a "shepherd's crook" appearance. Infected fruits also exude bacterial ooze. They eventually dry and remain attached to the branch

Cankers on branches or stems appear as dark, slightly sunken places with a small callus ridge at the edge The inner bark turns from green to brown, but the appearance varies depending on plant variety. Droplets of bacterial ooze may appear on the canker

Cultural Practices

the structure and mineral content of the soil are important in managing fire blight. Trees planted in poorly drained soil are more susceptible. Because fire blight development is favored by young, succulent tissue, avoid heavy application of nitrogen fertilizers or manure. Drip irrigation can reduce the high humidity associated with overhead irrigation and thus reduce disease severity.

Control

Remove and destroy newly infected young twigs as soon as possible. Do this when no rain is predicted for at least two weeks. It may be best to leave pruning until winter when the bacteria are not active. This reduces infection on the tree and the number of bacteria available to infect healthy blossoms and shoots.

In young twigs, make cuts at least 5cm below the visible edge of infection. Remove all blighted twigs and cankered branches. Prune limbs about 3 to 5 cm below the edge of visible infection.

To remove a canker on large stems, first make a cut through the bark down to the wood 1 to 2 cm outside the canker margin. The cut should not have any sharp angles. Next, cut and scrape away all infected bark down to the wood. Treat exposed wounds with

             COBOX               250g/100L.W

Biocontrol

it is now possible to use other bacteria to protect plants from the fire blight bacterium. Blight Ban is a Pseudomonas bacterium applied before and during bloom. It is available only in quantities for commercial application

Fungal Diseases

1-Pear Scab         Venturia pirina

Symptoms of pear scab are very similar to apple scab. Lesions on leaves and petioles begin as round, brownish spots that eventually become velvety in appearance. Within these lesions conidia are produced. Later in the season, small spots can be observed on the lower surface of the leaves. These are usually the result of late spring or early summer infections. Leaf infection of pear is not as common as apple scab on apple leaves.

Disease Cycle

Scab lesions on fruit occur on the calyx end and eventually on the sides of the fruit. As these lesions enlarge, they become dark brown and form large black areas as they coalesce. Lesions on immature fruit are small, circular, velvety spots. Darker, pinpoint spots develop as the fruit matures. Infected fruit often become irregular in shape.

Unlike apple scab, twig infections are common with pear scab. Early in the growing season, lesions on young shoots appear as brown, velvety spots. Later, these lesions become corky, canker-like areas. The following spring, pustules will develop within these over wintered lesions. These pustules produce spores (conidia) that perpetuate the spread of the disease.

The fungus over winters in leaves on the ground and also as mycelium in infected twigs. Infection of pear foliage and fruit occurs under conditions similar to those required for infection of apple by the apple scab fungus. Ascospores are the major source of primary inoculums. Infection occurs in the spring around the green-tip stage of flower bud development. Ascospores in the over wintered leaves are released as the result of rain and are carried by air currents to young leaves and fruit. Ascospores continue to mature over a six to eight week period.

Conidia are the source of secondary inoculums and are produced in either the primary lesions initiated by ascospores or within pustules on infected twigs. Many secondary cycles may occur over a growing season. The length of the wetting period and temperature required for infection depend on the number of hours of continuous wetness and the temperature during this wetting period. The Mills chart for determining apple scab infection periods along with a leaf wetness recorder or hygrothermograph can provide the information for determining the infection periods for pear scab. Scab lesions may develop in as few as eight days after infection on young leaves and in as many as two months on older leaves. Fruit are also more susceptible when young; however, mature fruit can be infected if the length of wetting period is sufficiently long.

Control

             KUMULUS-S                         250g/100L.W
             COBOX                                  250g/100L.W
             POLYRAM DF                      200g/100L.W

2- Armillaria Root and Crown Rot (Oak Root Fungus)

Casual organism Armillaria mellea

Symptoms

Affected trees usually show a general decline in vigor over many years. Sometimes trees that look healthy will suddenly wilt and die in a matter of weeks. The above ground symptoms are similar to other root problems, including too much water, Phytopthora root rot. The key symptom to look for is trees that are declining in patches and the patches seem to get larger each year.

To confirm the presence of Armillaria, dig around the crown of the tree and scrape off the bark on small sections of the crown and main roots. It should be easy to see the dense, fealty, creamy white-colored plaques of mycelium between the bark and the wood. Infected wood will have a strong mushroom smell and feel slightly spongy. Sometimes it may be difficult to locate the mycelium in the earlier stages if the infection has not yet moved up to the crown. Dark brown to black rhizomorphs (structures that resemble shoestrings) sometimes can be seen on the root surface. Sometimes, large, densely packed, honey-colored mushrooms form at the base of infected trees in late fall/early winter after rains. When removing dead or declining trees with a backhoe, be sure to check for signs of Armillaria root and crown rot. There are other wood-rotting fungi that also have dense white mycelium, so submitting samples to a lab may be necessary for positive diagnosis

Favorite Conditions and disease cycle

          Armillaria root and crown rot is most active when the soil is cool and moist. The pathogen survives in the soil on the roots of infected hosts from one year to the next. In the absence of a living host, it can survive for several years on old infected roots or other woody material buried in the soil

          the fungus can be spread on infected woody material carried by farm machinery or flood water and the chances are very high that the inoculum already exists in the soil on old decaying roots. When these roots or rhizomorphs come in contact with the roots of a healthy, susceptible host, they infect the healthy roots. Most pear orchards along waterways probably have some level of Armillaria present in the soil 


3-Anthracnose (Bull's-eye Rot)

Casual organism Pezicula malicrticus

          Infection occurs in the fall, but cankers will not appear until spring. Small injuries may facilitate penetration, but the fungus can penetrate uninjured bark. The canker grows actively only 1 year; however, the fungus continues to live 2 or 3 years in the dead canker tissue and produces large numbers of spores. Old infected orchards and nursery stock can be sources of this disease

Symptoms

 Cankers are most abundant on smaller branches but may be on larger limbs or on trunks of young trees. Complete girdling often results if more than one canker is on a lime

            the first apparent sign of an infection is the formation of a small, circular, reddish brown spot on the bark extending to the underlying tissues. Development of these cankers is arrested during winter. The canker expands most rapidly along the branch in spring. The cankers cease to extend and a well-marked crack forms, delimiting the canker from the surrounding healthy tissue. The surface of the canker becomes shrunken and shriveled as surrounding tissue continues to grow during the summer. The dead tissue gradually disintegrates and falls out. All that remains of it may cling to the wound for several years, forming "fiddle strings" across the longitudinal face of the canker.

During summer, numerous little pustules (acervuli) appear on the canker's surface, first at the center of the area and later out to its margin. Fungus spores mature in late summer and early fall and are scattered by rain and wind. Cankers 1 year old or more will not enlarge but are a fruitful source of fungus spores.

Control

             COBOX                                  250g/100L.W
             POLYRAM DF                      200g/100L.W

4- Powdery Mildew

Causal organism Podosphaera leucotricha

A fungus that over winters in terminal buds of pear

Leaf and terminal infection seldom cause economic losses except in the nursery. 'Bartlett' rarely has a problem with this disease.

Infected terminal buds of pear and sometimes pear develop into shoots covered with conidia. Spore dispersal is favored by wind and warm temperatures but inhibited by leaf wetness.

Symptoms

On pear fruit, white mycelium is visible until early June when it sloughs off, leaving a russeted patch where cells died. The russeted area expands as the fruit enlarge. Infected terminal buds have an open pointed appearance.

Life Cycle

On Pear the fungus over winters in terminal buds and is most severe in a season following a series of mild winters. Severe winter temperatures can reduce mildew pressure by killing infected buds, which are more susceptible to winter injury than healthy buds. As infected buds open in the spring, powdery mildew spores (conidia) are released to initiate primary infections on blossoms, young leaves, and fruit. Infections causing fruit russet can occur from about 3 weeks before bloom to 3 weeks after bloom. Additional conidia are produced on infected leaves and fruit which cause secondary infections. There is multiple generations' pear year, with trees susceptible as long as they are actively growing. Powdery mildew is favored by moderate temperatures (10-25 °C) and high relative humidity

control

             KUMLUS-S         200-300gL.W
             BELLIS                50g/100L.W                                                           

Crown and Collar Rot of Pear Trees

The causal organism Phytophthora ssp

Symptoms

Collar rot is observed as dead areas on the trunk called cankers between the soil line and crown roots. Cankers are difficult to detect when young, but as they enlarge, they darken and become slightly depressed. To be observed, the soil must be removed from the trunk of the tree. These cankers may only partially girdle the tree but if conditions remain favorable for the fungus, they will completely girdle and kill the tree.

This disease is not easily diagnosed from symptoms in him top of the tree. Scattered yellow leaves occur on trees in id-season. In late September, affected trees often develop reddish or purple cast in the foliage. Infected trees usually aver sparse foliage and low vigor. Foliar symptoms may pear only on branches directly above the canker, while the remainder of the tree appears normal and continues to bear fruit some trees may be diseased, but remain alive for 2 to years, while others will be killed within a single summer.

Collar rot can be found in young orchards as well as older plantings. It is especially serious when replanting in old orchard sites. Irrigation greatly influences the disease since the fungus is a water mold. It is more serious in heavy, poorly drained soils than in light, well-drained soils, although it can occur in almost any soil when improperly irrigated.

The fungus can be introduced into an orchard on planting stock, irrigation water or on contaminated farm implements. Other root problems may cause similar above ground symptoms and thus confuse diagnosis. Winter injury may predispose the tree to invasion by secondary invaders. Mice or other rodents may girdle the tree at the soil line causing above-ground symptoms similar to root rot. The only positive diagnosis is the appearance of the cankers and isolation of the fungus.

Control

Collar rot is difficult to control because it is an erratic disease and there is incomplete knowledge about the disease cycle. When infections are discovered, it is usually too late to eradicate the disease and save the tree.
The following control practices should be used to prevent or decrease collar rot:

1. Choose resistant varieties and rootstocks.
2. Select light soils with good drainage for orchard sites
3. Plant Shallow
4. Plant vigorous Phytophthora-free trees
5. Provide tree support
6. Preventive
7. Control after infection

Pear Leaf Spot

casual organism Mycosphaerella pyri

the pear leaf spot fungus, Mycosphaerella pyri, infects the leaves of pear, quince, and occasionally apple trees. Numerous leaf spots can produce defoliation. Fortunately, this does not often occur before fall, except in nurseries.

Symptoms

Mature leaf spots are easily recognized by their grayish white centers with sharply defined margins. Appearing first on upper leaf surfaces as small, brown lesions, they enlarge to 1.5 to 2.0 cm in diameter. The borders become dark brown, and small black pimples appear in the centers.

Disease cycle

Sexual spores are produced on over wintered, fallen leaves and are carried by air currents to newly formed leaves. About a month after infection, new spores are generated in the centers of the grayish white leaf spots, from which they are washed by rain to other leaves. These secondary infections usually peak in late summer or early fall.

Control

             COBOX     250g/100L.W
             BELLIS     50g/100l.w


 Late Leaf Spot

Introduction

Susceptible pear cultivars affected by late leaf spot often are defoliated by midsummer, resulting in dwarfing of fruit and reduction of fruit buds. Infected fruit is worthless since it is usually cracked, disfigured, or misshapen. In the nursery, early defoliation and twig infection result in stunted growth of trees.

Symptoms

Leaf spot can be found on petioles, leaves, shoots and fruits. Initial lesions on leaves are tiny, round, purplish-black spots, which quickly enlarge to 1.5 to 2.0 cm in diameter and usually have a blackish-brown center .Spots coalesce and severely infected leaves fall to the ground prematurely. A small black acervulus may develop in the center of each lesion, from which conidia ooze in a creamy, white mass in wet weather.  Fruit lesions are larger than those on leaves and cause the fruit to crack and drop. Lesions on current season's shoots may be observed as small inconspicuous, purplish-black spots. Some lesions develop into superficial cankers, but most are walled-off during the next growing season, so that cankers rarely persist in two-year-old wood.

Control

             COBOX     250g/100L.W
             BELLIS     50g/100L.W

Fruit rot

Brown Rot on Pear

Causal organism
Monilinia fructicola and M. laxa can incite blossom blight, a twig and branch dieback, and a fruit rot of several Prunus sp

Fungi survive year to year on infected twigs, branches, old flower parts, or mummified fruit. Conidia are produced on infected plant debris in the tree when the temperature is above 20C. A small, mushroom like structure (apothecium) can be produced on fruit that drops to the ground. Wind and rain blow spores (conidia and ascospores) to healthy blossoms in spring to begin the infection process during wet weather

Control

             BELLIS                        50g/100L.W
             KUMULUS-S               250g/100L.W

Gray Mold

Causal Organism:
The causal agent of gray mold is Botrytis cinerea Pers

Gray mold is a common post harvest disease on apples and pears wherever these fruits are grown worldwide. This disease can cause significant losses on both apples and pears during storage. Losses as high as 20-60% due to gray mold are not uncommon after an extended period of storage, particularly on fruit that were not treated with fungicides prior to storage, because gray mold has the ability to spread from decayed fruit to surrounding healthy fruit through fruit-to-fruit contact during storage.

Gray mold originates primarily from infection of wounds such as punctures and bruises that are created at harvest and during the post harvest handling process.

Stem-end gray mold is common on pears and also occurs on apples .Calyx-end gray mold has been observed on pears in the Pacific Northwest but generally is not very common.

The decayed area appears light brown to dark brown and color is similar across the decayed area. The decayed area is spongy, and diseased tissue is not separable from the healthy tissue, which is different from blue mold (a soft decay)1. Under high relative humidity conditions, fluffy white to gray mycelium and grayish spore masses may appear on the decayed area. The internal decayed flesh appears light brown to brown at the margin. Generally, gray mold does not have a distinct odor, but in advanced stages decayed apples may have a “cedar-like” smell. In advanced stages, the entire decayed fruit may appear “baked” and eventually may turn softer than in the early stage
Control

             BELLIS                        50g/100L.W
             KUMULUS-S               250g/100L.W

3- Mucor Rot

Mucor rot occurs on both apples and pears. Although it can cause significant losses of fruit, Mucor rot is generally not a major problem, particularly when good harvest management and water-sanitation practices at packing are implemented.

Symptoms

Mucor rot originates primarily from infection of wounds on the skin of fruit. The decayed area appears light brown to brown with a sharp margin. The decayed tissue is very soft and juicy and can be readily separated from the healthy tissue. Gray mycelium with dark sporangia may appear on the decayed area. Mucor rot fruit has a sweet odor. Without the signs of the pathogen present on decayed fruit, Mucor rot can be mistaken as blue mold, particularly in the early stage of symptom development

Causal Organism Mucor piriformis E. Fischer.

Diseases cycle

Mucor piriformis is a soil borne pathogen and survives in the orchard soil. The pathogen enters packing facilities through infested soils or organic debris adhering to field bins. Drench solutions and dump-tank water are the primary source of inoculums for fruit infection at drenching and packing. Mucor piriformis may infect the stem, calyx or wounds on the skin of fruit.

             BELLIS                50g/100L.W

4- Black Rot of pear

Casual organism Botryosphaeria obtusa

The fungus attacks the fruit, leaves, and bark of pear trees and other pomaceous plants. The fungus is a vigorous saprophyte and may colonize the dead tissue of many other hosts. However, its parasitic activities are confined mainly to pome fruits.

The disease may occur in three forms: a fruit rot, leaf spot, and limb canker on apple trees, and a fruit rot on pear and quince. In northern regions, losses from black rot result principally from the cankering of large limbs and dieback of twigs and branches. Losses from fruit rot and defoliation resulting from leaf spot can be considerable, especially in warm, humid areas of southern and central fruit-growing regions of the eastern United States.

Symptoms

The first signs of black rot are small, purple spots appearing on the upper surfaces of leaves and enlarging into circles 1.5 to 2.0 cm. in diameter. Leaf margins remain purple, while the centers turn brown, tan, or yellowish brown. After a few weeks, secondary enlargement of leaf spots occurs. Because this is not a uniform expansion, the spots become irregular or lobed in shape, at which time they assume a characteristic "frog eye" appearance: a purple margin with a zone of dark brown surrounding the tan-to-gray center. Small, black pycnidia (pimple like fruiting bodies of the fungus) may appear in the centers.

Infected areas of branches and limbs are reddish brown and are sunken slightly below the level of surrounding healthy bark. These cankers may expand each year, a few eventually reaching several feet in length. The margins of older cankers are slightly raised and lobed, and the bark within their centers usually turns light-colored, loosens, and scales off raggedly. This characteristic is not confined to black rot cankers, so it is not a good diagnostic symptom. Pycnidia form on dead wood of the cankered areas.

Fruit rot usually appears at the calyx end of the fruit. It can originate at any wound that penetrates the epidermis, including insect injuries. There is usually one spot per fruit, a characteristic that distinguishes black rot from bitter rot. Initially, the infected area becomes brown and may not change in color as it increases in size, or it may turn black. As the rotted area increases, often a series of concentric bands form, darker bands of mahogany brown to black alternating with brown bands. The flesh of the decayed area remains firm and leathery. Eventually, the apple completely decays, dries, and shrivels into a mummy. Pycnidia, containing spores of the black rot fungus, appear on the surface of rotted tissue.

Disease cycles

The fungus over winters in fruiting bodies (pycnidia and perithecia) on dead bark, dead twigs, and mummified fruit. It can invade almost any dead, woody tissue and is frequently found in tissue killed by fire blight. Early leaf infections often are visible as a cone-shaped area on the tree, with a dead twig or mummified fruit at the apex.

In the spring, black pycnidia and perithecia release conidia and ascospores, respectively. Conidia may continue to be produced during wet periods throughout the summer and may remain viable for long periods. When wet, the pycnidium produces a gelatinous coil containing thousands of spores. Disseminated by splashing rains, wind, and insects these spores can infect leaves, the calyxes of blossoms, tiny fruit, and wounds in twigs and limbs. Leaf infection develops during petal fall, at which time conidia attach, germinate in a film of moisture within 5 to 6 hours, and penetrate through stomata or wounds. Infections of fruit and wood may not become visible for several weeks.

Initial fruit infections occur during the bloom period but are not usually apparent until midsummer as the apple approaches maturity. Throughout the growing season, infections occur through wounds. Harvest injuries may become infected and the fruit may decay during or after storage, especially if the fruit was harvested during a wet period. Dead fruit spurs or twigs, particularly those killed by fire blight, pruning wounds, winter injuries, and sun scald, are commonly invaded by the black rot fungus.

Control

Timing of chemical treatments and cultural control strategies can affect the level of control achieved for black rot. Management programs based on sanitation to reduce inoculums levels in the orchard are the primary means of control.
1. Carefully prune and dispose of dead wood. This should be an important component of both current-season and long-range management.
2. Prune and remove cankers at least 20 cm. below the basal end; properly dispose of prunings by burial or burning.
3. Remove all mummified fruit.
4. Control fire blight by pruning out infected wood or controlling insect vectors. USE

             COBOX     250g/100L.w

Insect on pear

Pear Aphids

Green peach aphid: Myzus persicae
Cotton aphid: Aphis gossypii
Bean aphid: Aphis fabae

several aphid species occasionally attack pears; the most common are green peach aphid, cotton aphid, and bean aphid. These aphids over winter as adults on various weeds and field crops in or outside the orchards. Usually after pear bloom, when trees are growing rapidly, these aphids appear on foliage and shoots, establishing colonies and several generations may occur in cool spring weather.

Green peach aphid is light green in color. On adults a dark blotch in the middle of the abdomen serves to distinguish this species from others. Cotton aphid is generally dark green, but immature forms may be yellowish. Bean aphid is dark colored and seems to prefer sucker shoots in the center of the tree. Both green peach aphid and cotton aphid attack shoots all over the tree.
amage

Aphid feeding causes pear foliage to curl and the growth of shoots to be stunted. This type of injury is of minor importance. Most of the damage is caused from aphid feeding directly on fruit and production of honeydew, which falls on the fruit. Honeydew causes fruit lenticels to darken, giving the pear a russeted appearance. The presence of honeydew also makes the fruit sticky and a black fungus grows in this honeydew, giving the fruit a sooty appearance. This contamination and russetting will cause fruit to be culled from fresh shipping.

Control

             APHOX               50g/100L.W
             MOSPILAN        25g.LW


Pear Spider Mites

Two spotted spider mite: Tetranychus urticae
Pacific spider mite: Tetranychus pacificus
McDaniel spider mite: Tetranychus mcdanieli

DESCRIPTION OF THE PESTS

          Adult female mites are yellow in color. Feeding mites have dark spots on either side of the body. The tiny, spherical, colorless to light, straw-colored eggs are distributed over the infested area. Over wintering females are orange, and hibernate under bark scales on the tree and in trash on the ground. They move up the tree in late March and April, feeding on leaves. Rapid reproduction occurs in hot, dry weather and the infestation peaks in July and August.

Damage

Webs pinning mites produce a characteristic blackening of pear leaves when they feed. Pear trees can tolerate fewer web spinning mites than European red mites. Usually two to three mites feeding near the midrib of a leaf produce black areas from the midrib to the margin. This blackening may appear even after mites have been controlled, especially if a period of hot weather follows the spray application. High mite populations may cause defoliation. Severe defoliation can stunt fruit and may cause the trees to bloom in fall, thus reducing next year's crop. However, if defoliation is limited to water sprouts in the top or interior of the tree, it will not adversely affect the crop or tree.

Control

             CHALLENGER           40cm/ 100L.W
             ORTUS                         50cm/100 L.W    


Scale insect of pear

San Jose scale (Aspidiotus perniciosus Comstock) is the most important of the scale insect injuries discussed. San Jose scale may occur wherever pear is grown.

The insect cause injuries on pear fruit.

Many years ago scale insects were serious orchard pests, but presently they are not a problem in properly sprayed orchards.

Typical scale injury appears on pear fruits as small red spots about 1.5 to 2.0 cm in diameter. At the center of each of these spots is a light-colored area, marking the place occupied by the tiny insect before it was rubbed off in the handling of the fruits during or after harvest. In depressed areas, such as the calyx or stem ends of the fruits, the scales may still be attached. The adult scale is less than 1.5cm. In diameter, gray to grayish brown with a small dirty yellow nipple-like center surrounded by a depressed ring. Occasionally a small black scale, the stage that lives through the winter, is found.

Red spots on apples may also be caused by early stages of fungus infection, green aphis injury, spray injury, or other causes, but none are typical of scale insect injury and they should be readily distinguishable.

Control

             MOSPILAN                  25g/100L.W
             APPLAUD                    100cm/100l.w     
             CHALLENGER           40cm/100l.w