Apple Diseases
Associated Documents:
Biocontrol
Coccinellidae as Predators
Disruption of Wooly Aphid
Question:
In the area of Wardak, Afghanistan, we have a lot of apple orchards (Varieties Reported: Mahali, Summered, and Lebnani Zard/Mutsu (discrepency on name, but it is a yellow variety). When out on my missions, numerous villages near Mamaki in Maydan Shahr District have been experiencing some issues with their apples in the early development stages. Villages that reported this were Manyan, Alakhel, and Rahimkel (if you have a map); however, I believe this problem is endemic throughout my AO in Northern Wardak (from the city of Maydan Shahr along Hwy 2 toward Jalrez).
Due to translation problems, the description of the disease is a little vague. This occurence happens in spring when the apples are at their smallest. The tree bark is reported to become white and then--when there is fruit--the fruit also becomes white "like snow," as the village elders put it. Each village called this "Barfak" or "Sirhak" (spelled phonetically).
The solution that they used in the past (but did not work last year) was something called "Supper Sid First" from Pakistan; it sounds like they are saying "Supersite" (spelled phonetically), but "Supper Sid First" is how the terp wrote it down. They described this solution to be of a red consistency that you add water to and then it creates a fog (fumigation?). They did not have a box left over from last year and I have not been able to verify this solution.
I am sorry to be vague and not to understand this completely. I am an almond farmer by trade, which is why I immediately thought it might be a type of aphid. If you could send me any and all material you think might be of help, that would be great (I am not expecting you to know it off the top of your head). Additionally, if we cannot narrow it down, I can always wait until March when this occurs and take pictures for you to better understand the issue.
As an aside, the main crops here seem to be apples, so if you have any academic papers on the various apple varieties primarily grown in Wardak (i.e. Red Chief, Blushing Golden, Granny Smith, Tor Kulu, Mahali, Wellspur, Lebnani Zard, Lebnani Sorkh, Double Red Delicious, Royal Gala, Mutsu, Summered), feel free to send the information to me.
Slightly off the topic, I am also in the middle of creating technical demonstrations on apiculture, so anything to do with beekeeping in the developing world would be great (though I am finding there to be a sufficient amount of material from various academic institutions, including an FAO demonstration in Pakistan in 1999 to review).
Thanks in advance.
Response:
Control Codling Moth on Fruit Trees
Natural control Birds are important predators of hibernating larvae that are under loose bark. Parasites can attack eggs and larvae of the developing codling moth. Some worms always escape natural control; chemical controls are thus usually needed because of consumer demand for blemish-free fruit.
Physical control Pick up and place fallen fruits in a plastic bag and put the bag in the trash weekly; larvae in these fruit will then not reach adulthood in your orchard.
Physical control Attach corrugated cardboard strips (two to four inches wide) tightly to the tree trunk and scaffold branches in June and August to provide a site for the larvae to make their cocoons. Remove and destroy the strips after cocoons are formed. Before the bands are attached, the bark should be scraped to remove loose pieces that would prevent a tight fit by the strips.
Chemical control Repeated applications of insecticide every 10 to 14 days are usually needed from petal-fall to near harvest. Sprays are most effective when applied just before newly hatched larvae attempt to enter the apples. If you are using a pheromone trap to monitor codling moth, the best time to spray is two weeks after the first moth catch or one week after a peak catch. Use an all-purpose fruit tree mixture or the insecticide phosmet (Imidan). Carbaryl (Sevin) will also control codling moth, but it should not be used within 30 days of full bloom because fruit thinning will result.
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Control Strategies of Spider Mites
Early detection of spider mites, before damage is noticed, is important. The tiny spider mites can be detected by taking a piece of white paper or cardboard and striking some plant foliage on it. The mites can be seen walking slowly on the paper. If 10 or more mites per sample are common, controls may be needed.
Option 1: Cultural Control - Syringing Since rainy weather seems to knock off spider mites, using a forceful jet of water from a hose (syringing) can perform the same task. A regular syringing can keep spider mites under control on most ornamental plants in the landscape. This technique also helps conserve natural predators.
Option 2: Cultural Control - Quarantine and Inspection The twospotted spider mite is often introduced on infested bedding and house plants. When purchasing new plants, carefully inspect the lower leaf surface for any signs of mite activity. New house plants should be quarantined from other plants until you are sure that no mites are present.
Option 3: Biological Control - Predators There are numerous insects (lacewings and lady beetles) that prey on spider mites. However, the most commonly sold predators are other types of mites. Predatory mites (usually Phytoseiulus spp., Amblyseius spp. Or Metaseiulus spp.) can be purchased and released onto infested plants. Be sure to check listings to determine which species is appropriate. Some species are host specific and each predator works better under different weather conditions. If predators are used, do not apply pesticides that will kill them.
Option 4: Chemical Control - "Soft Pesticides" Most spider mites can be controlled with insecticidal oils and soaps. The oils, both horticultural oil and dormant oil, can be used. Horticultural oils can be used on perennial and woody ornamentals during the summer at the 1 to 2 percent rate. Higher rates of horticultural oil (3 to 4 percent) or dormant oil are useful for killing mite eggs and dormant adults in the fall and spring. The insecticidal soaps are useful in the warm season. Remember that mites are very tiny and soaps and oils work by contact only. Therefore, thorough coverage of the plant is necessary for good control.
Option 5: Chemical Control - Miticides Spider mites are usually not killed by regular insecticides, so be sure to check the pesticide label to see if "miticide" is present. Pesticides claiming "for mite suppression" are usually weak miticides and will not perform well. There are few products available to the homeowner. Dicofol (=Kelthane) is registered for over-the-counter use but is difficult to find. Acephate (=Orthene), dimethoate (=Cygon), chlorpyrifos (=Dursban), diazinon, disulfoton (=Di-syston), and malathion have over-the-counter product labels but are considered weak miticides.
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Woolly Apple Aphid
Chemical Control
An insecticide can be applied if woolly apple aphid is detected at damaging levels on above-ground parts of trees. Insecticides are most effective if applied when the aphid is in the active crawler stage and is just moving up into the tree. This may occur in late-spring or not until mid-summer. Thorough coverage of the canopy is needed for insecticide to be effective. Because of the aphids' waxy covering, high volume application is needed to get thorough spray coverage. A second application may be needed two weeks after the first if aphids continue to be detected.
Insecticides used to control woolly apple aphid in commercial orchards are dimethoate (Cygon), endosulfan (Thiodan), chlorpyriphos (Lorsban), or methyl parathion (Penncap-M). Home gardeners can use diazinon or insecticidal soap.
Woolly apple aphid infestations on rootstocks cannot be controlled by insecticides.