Nectarine diseases By Allah Dad Khan Provincial Coordinator IPM KPK MINFAL
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This document discusses several diseases and pests that affect nectarine trees: - Brown rot fungus causes fruit to rot on the tree and can be prevented by removing infected fruit and using fungicide. - Peach scab fungus causes cracking and rotting of fruit which makes canning difficult; it is controlled with fungicide applications. - Powdery mildew fungus affects leaves and fruit; proper variety selection, fungicide, and maintenance can prevent it. - Leaf curl fungus causes defoliation; fungicide application in fall or spring stops the fungus.
Nectarine diseases By Allah Dad Khan Provincial Coordinator IPM KPK MINFAL
- 2. Nectarine Diseases A Lecture To ToT trainees ( FFS) By Mr. Allah Dad Khan Provincial Coordinator IPM KPK MINFAL Pakistan
- 3. Peach Brown Rot Symptoms Brown rot on fruit Brown rot, caused by the fungus Monilinia fructicola, causes the fruit to rot away while still on the tree. In its last stages the fruit is entirely brown and looks whithered and dried out. The fungus can live in many temperatures and climates, but it particularly loves moist climates. The rot can also turn flowers brown and cause new twigs to die off. To prevent the spread, make sure to clear away affected fruit, twigs or flowers. Do not compost the remains, as the fungus spores can live in compost and spread to the rest of your garden. A fungicide can also stop the spread of the fungus. Good air circulation and a drier enviornment also helps prevent rot.
- 4. Peach Brown Rot Symptoms of brown rot on peach blossom Symptoms of brown rot on peach twigs and blossoms
- 5. Peach Brown Rot Symptoms of brown rot on fruits Brown rot on fruit
- 6. Peach Scab Cladosporium carpophilum Symptoms Scab on peach fruit Peach scab is caused by a fungus called Cladosporium carpophilu. It is most often found in warm, moist and humid areas, such as in the South. However, it can affect peach trees worldwide. The fruit will often crack and rot within those cracks, without much affect to the taste of the fruit. However, scab makes it harder for the peach skins to slip off during the canning process. To prevent scab, use a chemical or organic fungicide just as the blossoms fall of the trees and for the ensuing month. Pruning and cleaning up fallen fruit and leaves will also prevent the continued spread.
- 7. Peach Scab Scab symptoms on peach twigs Scab symptoms on peach fruit
- 8. Peach Scab Scab symptoms on peach fruit Scab symptoms on peach fruit
- 9. Peach Powdery Mildew Symptoms Powdery Mildew is caused by the fungus called Sphaerotheca pannosa and affects both garden plants and fruit trees. Leaves often fall off or develop abnormally, eventually growing a white fuzz. An entire harvest can be ruined by mildew if left unattended. Consider purchasing tree varieties that aren't susceptible to the disease. Fungicide and proper area maintenance are also good preventative practices.
- 10. Peach Leaf Curl Symptoms Leaf curl on peach Leaf curl is a fungal disease caused by Traphrina deofrmans. It causes defoliation and crop loss in practically every variety of peach tree. Fungicide application during the fall after most of the leaves have fallen or before budding in spring can stop the fungus.
- 11. Leaf curl Peach leaf infected with leaf curl Peach leaf curl symptoms
- 12. Peach Leaf Curl Peach leaf curl symptoms on young peach tree Peach leaf curl symptoms on foliage
- 13. Peach Leaf curl Peach leaf curl symptoms Peach leaf curl symptoms
- 14. Peach Bacterial canker Pseudomonas syringae Symptoms Canker on peach trunk Cankers on twigs at bases of flower and leaf buds, in pruning wounds or at the base of spurs which exude amber colored gum; cankers spread upwards and form sunken areas in winter; if pathogen enters dormant buds they may be killed or open normally in Spring before collapsing in early Summer; infected buds may be symptomless Cause Bacterium Comments Disease emergence favors high moisture and low temperatures in the spring; young trees particularly susceptible; trees grown in sandy soils that drain poorly are also susceptible Management Ensure that a suitable peach variety and rootstock is chosen based on geographic location and environmental conditions to prevent stress to tree which predisposes tree to canker disease; apply protective copper spray to trees before flowering; prune trees in early summer to decrease likelihood of infection
- 15. Peach canker Canker exuding gum on infected peach tree Peach tree with dark cankers on bark
- 16. Canker on peach trunk Canker on peach trunk Canker on peach trunk (bark peeled to show discoloration to tissue underneath)
- 17. Bacterial spot Xanthomonas campestris Symptoms Peach tree infected with bacterial spot Water soaked, angular gray lesions on the underside of the leaves which turn purple and necrotic in the center and cause a shot hole appearance if lesion center drops out; if lesions are present in high numbers on leaves they may become chlorotic and drop from tree; cankers develop on twigs either as raised blisters or as a dark area surrounding a bud that fails to open; in years of severe infection the entire fruit crop may be lost; lesions on fruit begin as small brown, water-soaked lesions which may exude gum Cause Bacterium Comments Periods of frequent rainfall during late bloom and early petal drop increase likelihood of fruit and leaf infection; infection is rare during hot, dry weather Management Avoid planting susceptible peach varieties in areas where disease is known; once disease is visible it can be difficult to control, protective copper applications in the Fall prior to leaf drop and/or application in early growing season may help prevent the disease; care should be taken as peach trees are very sensitive to copper
- 18. Peach Bacterial Spot Symptoms of bacterial spot on peach leaves Symptoms of bacterial spot on peach leaves
- 19. Peach Bacterial Spot Symptoms of bacterial spot on peach leaf Symptoms of bacterial spot on peach fruit
- 20. Peach Crown gall Agrobacterium spp Symptoms Large gall on trunk of peach tree Galls on roots and/or crown of tree which can range in size from so small they are not visible to the naked eye up to 10 cm (4 in) in diameter; galls first become visible as white, fleshy swellings that grow rapidly and become tan to brown in color; galls typically develop at the site of a wound and new galls form adjacent to old ones the next year Cause Bacterium Comments Infection with crown gall begins at the site of plant wounds; disease emergence is favored by poorly- drained, alkaline soils and previous feeding damage by nematodes Management Chemical control of the disease is generally ineffective; an effective bacterial biological control is available for commercial production; cultural control methods include: planting only certified, disease-free material, planting peach in well-draining soil, rotating infected fields with a non-host before peach is planted and also using good sanitation practices
- 21. Crown Gall Symptoms of crown gall on trunk of peach tree Galls on roots of peach tree
- 22. Crown Gall Crowm gall symptoms Symptoms of crown gall on trunk of peach tree
- 23. Crown Gall Gall on peach tree Galls on peach roots
- 24. Peach Shot hole disease Wilsonomyces carpophilus Symptoms Shot hole lesions on peach fruit Brown lesions with purple edge on fruit, twigs and buds; holes in leaves due to lesions which have dried and dropped out; brown lumps developing in the center of lesion (visible with hand lens); buds turning brown or black and exuding sap; tan lesions with brown margins which exude sap on twigs Cause Fungus Comments Disease emergence favors wet, windy conditions Management Application of Bordeaux mixture before rains in Fall are sufficient to protect dormant buds and twigs
- 25. Shot Hole Shot hiole symptoms on peach fruit Shot hole lesions on peach fruit
- 26. Peach Silver leaf disease Chondrosterum pupureum Symptoms Leaves have a silvery appearance; if infection is severe the leaves may curl upwards and become necrotic; death of individual limbs or entire tree may occur; fungal fruiting bodies appear on the surface of the dead bark Cause Fungus Comments Pathogen is spread via spores released after rainfall during periods of high humidity and can enter trees through pruning wounds; risk of infection is increased if tree is pruned during late winter or early spring; trees also susceptible when they are heavily pruned Management Control of silver leaf disease is difficult and infection can be widespread after rainfall in areas where the disease is present; strategies to reduce the incidence of the disease include: removing all plant debris e.g. pruning waste, stumps, and logs; pruning tree during dry periods and treating large pruning wounds with fungicidal dressing
- 27. Phytophthora root and crown rot Phytophthora spp. Peach tree showing symptoms of Phytophthora infection
- 28. Peach Rust Tranzschelia discolor Symptoms Rust spots on peach leaves Pale yellow-green spots on both upper and lower leaf surfaces which are angular in shape and turn bright yellow in color; spots on lower leaf surface develop orange-red spores Cause Fungus Comments Fungus overwinters in twigs or in leaves which remain attached to the tree Management Rust can be prevented by spraying trees with protective fungicides; application is usually carried out one, two and three months before harvest in areas prone to early season outbreaks of the disease and after harvest in areas where disease is less problematic or emerges later in the season
- 29. Peach Rust Rust symptoms on peach leaves Rust symptoms on peach leaves
- 30. Plum pox virus Plum pox virus (PPV) Symptoms Symptoms of plum pox on peach fruit First expanding leaves exhibit chlorotic veinclearing and veinbanding; lamina twisted and distorted; fruit show dark rings, lines and spots; symptoms on fruti may disappear on ripening; fruit may be deformed Cause Virus Comments Virus is transmitted by aphids but most common method of spread is diseased plant material Management Plant certified healthy material; remove infected trees from orchard; chemical sprays to control aphids may prolong spread of virus
- 31. Peach Fruittree leafroller Archips argyrospila Symptoms Fruittree leafroller Leaves of plant rolled and tied together with silk webbing; feeding damage to rolled leaves; defoliation of plant; silk webbing may also be present on fruits and fruits may have substantial scarring from feeding damage; larvae wriggle vigorously when disturbed and may drop from plant on a silken thread Cause Insect Comments Only one generation of insect per year Management Monitor plants regularly for signs of infestation; remove weeds from plant bases as they can act as hosts for leafrollers; avoid planting pepper in areas where sugarbeet or alfalfa are grown nearby; Bacillus thuringiensis or Entrust SC may be applied to control insects on organically grown plants; apply sprays carefully to ensure that treatment reaches inside rolled leaves