2001 – Current Pest Report – Visual Observations

Tree Stage for McIntosh trees: 
4/2/01 – Silver tip
4/9/01 – buds breaking
4/18/01 – 1/4 inch green
4/20/01 – 1/2 inch green
4/23/01 – tight cluster
5/1/01 – pink
5/3/01 – bloom
5/12/01 – petal fall

Visual Observations
8/9/01 – I haven’t done much scouting this week because I am spending the week collecting leaves and soil for leaf tissue analysis. I did check the one Early Williams tree where I set up 9 apple maggot fly traps. Over seven days I caught a total of 58 apple maggot flies. That averages to more than 6 AMF per trap. If it has been more than 14 days since you applied an insecticide, you may want to reapply now.
– I found quite a few two spotted spider mites in one orchard. Two spotted mites are usually controlled well with an application of Vendex plus a chemical such as Tactic or Silwet. Vendex and oil work well together too, but usually growers resist using oil because they want to use Captan.
8/3/01 – Even more apple maggot flies caught! Many orchards are above the threshold of 1-2 AMF per trap. Remember I set up 9 traps in one Early Williams tree to try and trap out apple maggot flies in that tree? On July 16 I caught 76 AMF in 5 days. I checked the traps again on 8/2 (after 16 days) and caught 130 AMF. The tree had even been sprayed with Imidan on July 19. Now is not the time to stretch too far between insecticide applications. Keep the interval to about 14 days.
– Rose leafhopper are still numerous in some orchards. Orchards sprayed with Provado for leafhoppers are still well controlled. Orchards sprayed with Sevin or Thiodan for leafhoppers may need to be re-treated. Check now on the underside of leaves for the small, white nymphs.
– I found a few adult leafminers on 8/2. These are probably new adults from the second generation. Soon they will begin to lay eggs for the third generation. We do not recommend spraying for the third generation leafminers because the generation is too spread out and can’t be adequately controlled.
– The yellow spider mites I’ve been refering to this summer seem to be well controlled now by mite predators. There may still be some instances where the yellow spider mites are causing problems. The mites are on the underside of leaves and tend to be located near the mid-vein. The mites cause a general yellowing of the foliage and may cause some brown patches to appear, primarily on the lower leaf surface. Yellow spider mites appear to be easy to control with miticides.
– European red mites are causing bronzing in some orchards. In many cases, mite predators are also building up and will hopefully control the red mites. If there aren’t enough predator mites (at least one predator per leaf) the pest mites will probably need an application of miticide.
7/31/01 – I caught more apple maggot flies today. I think the rain from last week did bring out more flies. I realize that northern RI received much less rain than southern RI, but there were more AMF caught in some orchards.
– I saw one apple with fly speck today. Spray with a fungicide if it has been 2 weeks since spraying Captan or 3 weeks since spraying Captan plus Topsin M.
– Still scout for European red mites, two spotted mites, and yellow mites. The spray threshold for mites is 5 mites per leaf or 75% of leaves with mites. I am still finding many mite predators. I especially find the bright yellow Z. mali mites.
7/23/01 – Apple maggot fly traps captures seem to be dropping off. I expect we’ll see another flush of apple maggot fly activity after we get a soaking rain. Also, many growers have applied an insecticide. Applying insecticides reduces apple maggot fly activity! When you look at the apple maggot fly capture chart, but sure to notice when traps were checked at a particular orchard. For instance, at East Farm I caught 17 flies on 3 traps today, but I hadn’t checked these traps for 3 weeks.
– Rose leafhoppers are still present and you can still spray for them if needed.
– It is definitely too late to spray for second generation leafminer. I expect to see second generation adults emerging in a week or so.
– Yellow mites continue to be found in many orchards. Luckily there are plenty of predators (Z. mali) in many locations. In most situations the predators are taking care of the yellow mites.
– Give me a call (874-2750) or email (hhf@uri.edu) about leaf tissue analysis samples (see 7/20/01 entry).
7/20/01 – I visited the orchard where the grower was planning on applying AgriMek against yellow spider mites, Eotetranychus carpini borealis. Well, he had not applied the AgriMek yet, he was going to apply it tonight. I thought I’d check out the trees and when I did I found most of the yellow spider mites had been killed by the predator mite, Zetzellia mali. I had seen some predator mites there last week, but not many. I think the predators were primarily eggs or small nymphs last week, and difficult to see. I was pleased to tell the grower not to bother with the AgriMek. Rhode Island apple growers, if you want me to check on predator numbers in your orchard next week email me at hhf@uri.edu.
– In June, Lisa Tewksbury and I took a Plum Pox sample from many RI peach orchards. All samples from Rhode Island were negative for the Plum Pox Virus.
– I’m trying to figure out how many leaf tissue analysis samples I’m going to take this summer. If you’d like me to come to your orchard and take a sample to send to University of Maine, send me an email. I’m planning on taking samples in early August. I believe the cost is $25 per sample. This is an excellent way to see what nutrients your trees need.
7/19/01 – Today I was mostly in orchards without apple maggot traps. I did see one live female apple maggot fly on a Lodi or Yellow Transparent apple (I forget which one). If you haven’t sprayed yet for apple maggots, now is probably a good time to do so. Half rates of Guthion or Imidan work well. Sevin will also control apple maggot fly but the control doesn’t last very long and Sevin is more harmful to mite predators (than Imidan and Guthion).
– Many orchards need to spray trees for rose leafhoppers. Look now on the underside of leaves for the small, white nymphs. Provado, Thiodan, or Sevin controls leafhoppers very well. Imidan and Guthion do not control rose leafhoppers.
– European red mites and yellow mites have been building in some orchards. You may remember I mentioned before that one grower with a high number of yellow mites used Apollo. The Apollo controlled the yellow mites very well. Another grower used Agrimek against the yellow mites. I have not been back to this orchard to check on the results (maybe I’ll get there tomorrow). Vendex also controls the yellow mites well.
7/16/01 – On 7/11, I set up 9 apple maggot fly traps in one very large Early William tree to try and trap out the apple maggot flies that were attracted to this early maturing tree. Today I checked the traps and found 76 apple maggot flies on these 9 traps! I also had 4 other traps set up throughout the orchard. On these 4 traps I caught a total of 8 amf. Apple variety really makes a difference! Each orchard is different too. In some orchards we rarely catch any apple maggot flies.
– Rose leafhoppers can be found now as adults, young nymphs and old nymphs. This makes leafhopper control challenging. I still think now is a good time to control leafhoppers.
7/13/01 – More apple maggot flies were caught this week. I’m catching them primarily on traps set up in early maturing varieties, but also on traps set up in Cortlands and Red Delicious. Early maturing varieties should probably sprayed now with an insecticide, but varieties that mature in Septmeber or later can probably wait a week before an insecticide is needed against apple maggot fly.
– Rose leafhoppers are ready to be controlled now. Check the underside of leaves, and if you find 25 nymphs per 100 leaves consider applying Provado, Thiodan or Sevin. I’ve heard Cornell Cooperative Extension is reporting that leafhoppers can be controlled with 1/2 ounce of Provado per 100 gallons of water.
– Second generation leafminer larvae are beginning to advance to the tissue feeding stage now. It is now or never if you wish to control second generation leafminer. Look on the underside of youngest leaves for the small mines. A method to decide about treating for leafminers is to examine the oldest leaves. If you find 13 old mines out of 100 old leaves, consider treating with Provado for this second generation. I repeat, it is nearly too late to adequately control the second generation.
– European red mites are bronzing some foliage. If you see bronzing, look for motile mites and treat with Pyramite if needed. I am also finding many yellow spider mites in some orchards. These mites look very similar to two spotted spider mites, but don’t have the spots. The yellow spider mites are typically found on the underside of leaves near the mid-vein. Yellow mites cause a yellowing or light brown patches to form on the underside of leaves. I’ve seen them do considerable damage in some orchards. I know they can be controlled with Vendex at 1 lb/100 gal plus Silwet or Tactic at 6 ounces per 100 gal finished spray mix. I do not know how well other miticide treatments work. One grower is trying Apollo and another is trying AgriMek. I’ll let you know how well these treatments work.
– Now is a good time to spray tree trunks with Lorsban to control dogwood borers. Three to four year old trees are extremely susceptible to borers. Lorsban, during this time of year, can only be applied to the tree trunks. Also, be sure to keep weeds down around tree trunks.
7/6/01 – Many apple maggot flies captured at URI’s ochard, but we have a built in population from last year because we didn’t spray a large section of the orchard. These flies did not need to migrate into the orchard – they were already there! We will spray Imidan early next week to control apple maggot flies. In commercial orchards, apple maggot flies need to migrate into an orchard since the flies were killed the year before by insecticides.
– I saw many more rose leafhopper nymphs today. I think next week will be a good time to control them with Thiodan or half rates of Provado.
-I found more potato leafhoppers on young as well as mature trees today. Remember, you only need to control potato leafhoppers on young trees, where you want maximum tree growth.
– Green apple aphids have been totally controlled by aphid predators (almost). Ladybug larvae are present in huge numbers. Ladybug larvae (Harmonia axyridis) look like black and red alligators (sort of).
7/2/01 – Rose leafhopper nymphs are beginning to hatch. They are tiny white insects on the underside of leaves. It’s too early to spray for them now because not many have hatched yet. Proper timing to spray against rose leafhoppers will probably be in about a week. Insecticide choices include Thiodan, Provado (one ounce per 100), or Sevin. Out of these three insecticides, Sevin will be the most harmful to mite predators.
– Leafminer second generation mines are becoming visible now. If you find many mines from the first generation (more than 13 mines per 100 fruit cluster leaves) consider applying Provado against the second generation. Proper timing for this application is probably in about a week. To control leafminers, Provado must be applied at the 2 ounce per 100 gallon rate and may need to be applied a second time, about 10 days after the first.
-I found many potato leafhoppers on young trees at one orchard. Potato leafhoppers are harmful to young trees because they stunt tree growth. Potato leafhoppers are not a problem on mature trees. Check on the under side of the terminal leaves for the small, pale-green leafhoppers. If your young trees have many potato leafhoppers, apply an insecticide.
6/28/01 – San Jose scale are visible on fruit now as red spots with a scale insect in the middle of each spot. I also found many crawlers still crawling around. The best time to treat for San Jose scale is when the crawlers first emerge in mid June and then again about 10 days later. If you are finding damage on the fruit now it is probably somewhat beneficial to spray now since the crawlers are still around; though it should be applied very soon. San Jose scale should be treated only if you know you have a problem. Guthion, Imidan, and Provado are effective against crawlers.
– Plenty of green apple aphids in all orchards, but plenty of predators too. Only spray for aphids if you find sticky aphid honeydew building up on the fruit. Thiodan or Provado at low rates (half rates or lower) control aphids well.
– Leafminers are still emerging as adult moths. I have yet to see any mines from the second generation, though I expect to find them soon. Now is not the time to spray for leafminers. Probably late next week will be a good time to spray for leafminers (using Provado).
-Leafhoppers (white apple and rose) are primarily adults now. I haven’t seen any nymphs of the rose leafhopper yet; I expect to start seeing them next week.
– I have caught 3 apple maggot flies on a total of 9 traps checked. The threshold for apple maggot fly is 1-2 AMF per trap. Insecticide should not be applied at this time to control apple maggot fly. Apple varieties that ripen in September or later probably do not need to be sprayed with an insecticide until late July.
– To control summer diseases on fruit apply Captan every two weeks or Captan plus Topsin M every three weeks. Flint and Sovran also control summer diseases well. These materials can be used only four times a season. Flint has a 14 day preharvest interval and Sovran has a 30 day preharvest interval.
6/25/01 – Not much going on in the orchards these days. The only problem I see is more leafhoppers than usual. In most instances the leafhoppers are adults and shouldn’t be sprayed now. I did see one orchard where many of the leafhoppers are still nymphs so a spray of Thiodan or Provado will probably be beneficial at this time.
– I do continue to see plenty of green apple aphids – but I see lots of predators too.
6/22/01 – I found a little bit of scab in a few orchards today. Scout now for the velvety, olive green lesions. If you can’t see lesions by now, your trees are probably scab-free and should remain so for the rest of the season. If you find more than a small amount of scab, consider applying Sovran or Flint to reduce apple scab spore production.
– Leafminer second generation adults have been emerging over the past week. The second generation mines will be developing soon. If you find more than 13 mines per 100 fruit cluster leaves from the first generation, consider applying Provado in about 1 week or so. The Provado should be applied when just a few of the second generation mines have advanced to the tissue feeding stage (when mines are visible from the upper leaf surface.) More than 90% of the mines should still be in the sap feeding stage. For adequate control, you may need to apply Provado a second time, about 10 days after the first application.
– I see leafhoppers flying around in most orchards. These could be white apple leafhoppers or rose leafhoppers. If they are rose leafhoppers, next generation nymphs should be appearing on the underside of leaves in about a week or so. If they are white apple leafhoppers, next generation nymphs won’t appear until August. Whichever species they are, you should not spray for leafhoppers at this time.
– I have not seen many potato leafhoppers yet this year. Be sure to check young trees for potato leafhoppers on the underside of leaves at the tips of branches. Potato leafhoppers can stop shoots growing. This is all right on mature trees, but not on young trees where you want as much growth as possible. If you find many potato leafhoppers on young trees, spray them with Imidan or Guthion. If that doesn’t control them use Provado, Thiodan or Sevin.
– Green aphids can be found in all orchards now. I am also finding aphid predators in all orchards. Don’t spray an insecticide for aphids, the predators will control them if you let them.
– European red mite threshold for June is 60% of leaves with motile mites.
– This year’s June drop seems larger than usual. I’m chalking this up to the freeze on May 7 stressing the trees.
6/18/01 – Wow, another big rain storm. I heard some areas received 6 inches of rain yesterday!
– I have not found any fresh plum curculio scars. Continue to check borders, but I really believe plum curculio are finished for the year.
– Until apple maggot fly, the only insects to be concerned with are rose leafhoppers, potato leafhoppers, and leafminers. For rose leafhoppers, don’t spray anything now. Wait for the next generation nymphs to appear in a couple of weeks.
– For potato leafhoppers, watch your young trees for leafhoppers on the growing tips. I did see a couple of potato leafhoppers today, but not many. Potato leafhoppers are generally not a problem on mature trees.
-Leafminers have begun to emerge as the next generation adult moths. Soon these moths will mate and lay eggs to begin the next generation mines. If you find more than 13 mines per 100 fruit cluster leaves, you may want to spray the next generation mines with Provado. The timing for this is probably in about 10-14 days. A second application of Provado (about 14 days after the first spray) is probably necessary to provide good leafminer control.
– I had hoped to find more leafminers killed by parasites. In the two orchards I checked, about 30% of mines were parasitized. This is the percent parasitized we usually find in the first generation mines.
– Continue checking for scab lesions until the end of the week. If you don’t find lesions by Friday you can certify yourself scab-free! If you do find more than just a few lesions, consider applying Sovran or Flint to reduce the number of scab spores produced.
– It should be a quiet time in the orchard now. Most orchards should not require an insecticide spray until apple maggot fly time in July.
6/11-6/14 – Sorry for the late update – computer problems!
-No fresh plum curculio scars found on trees sprayed since 6/2 – even though we received 1 – 2 1/2 inches of rain on 6/11 (washing off insecticide) and even though we’ve had great plum curculio weather for most of the week. Still, the wisest thing to do is check trees near woods and look for fresh scars. If you find fresh scars, apply Imidan or Guthion to border row trees.
-Rose leafhoppers have been migrating from roses to apples over the past week. If flying leafhoppers suddenly appeared in your orchard, they are probably rose leafhopper. If you find white stippling damage on older leaves along with flying leafhoppers, you probably have white apple leafhopper (or a combination of both species). Don’t bother spraying for them now. Wait until the next generation of leafhopper nymphs appear. If you have rose leafhopper, nymphs will appear within the next couple of weeks. Next generation white apple leafhopper won’t be around until August. There still may be some white apple leafhopper nymphs in your trees. If you have large numbers of nymphs now, these can be controlled with Provado, Thiodan or Sevin.
– Potato leafhoppers should be arriving soon. These feed on the end of branches causing the leaves to cup and turn pale. This is not a problem on mature trees, but should be controlled on young trees since potato leafhopper feeding reduces terminal growth. Imidan or Guthion will hopefully control potato leafhopper, but you may need to use Provado, Thiodan or Sevin.
– I’m finding lots of leafminer parasites at our URI orchard. I think about 60% of the mines are parasitized. I’ll let you know more next week.
– Mite threshold for June is 60% of leaves with motile mites.
– I’ve been looking for San Jose scale crawler emergence. They usually emerge around June 10th. As of June 14 I have not seen any crawlers. If you know you have a San Jose scale problem, use a magnifying glass to look at infested limbs for the tiny, yellow crawlers. Imidan or Guthion should be applied when crawlers first emerge and then again about 10 days later.
– Scab lesions have started to become visible. I’ve seen just a tiny bit of scab in commercial orchards. Check your orchard for lesions now.
6/8/01 – I found a lot of fresh plum curculio egg laying scars on trees not sprayed with an insecticide since the June 2 rain. If you have not sprayed since then, you should tonight or tomorrow morning. I think most of the damage I found occurred within the last 24 hours. I expect plum curculio to be very active over the next few days.
– White apple leafhoppers are primarily adults now. In nearly every orchard I see a few leafhoppers flying around. This is not the time to spray for them! If you need to control white apple leafhoppers you’ll have +to wait until the second generation nymphs are present in August.
– It is also too late to spray for first generation leafminer. If you find more than 13 mines per 100 fruit cluster leaves, consider spraying for the second generation sap feeding mines. The time for this is usually early July. Remember, if your crop is light, your trees can tolerate more leafminers.
– Green apple aphids are starting to build up. So are aphid predators. Give the predators a chance and don’t spray for aphids.
– European red mite summer eggs are beginning to hatch. The threshold for June is 60% of leaves with red mites. Mites are not such a problem as in years past since we have effective miticides: Apollo, Savey, and Pyramite.
– I finally found apple scab lesions on unsprayed apple leaves. Also, someone told me they saw scab on fruit. Check now for lesions! Probably the best materials to spray on scab lesions is Sovran or Flint.
– I consider primary scab season over.
– Don’t forget the twilight meeting June 14 at Don Smith’s on route 102 in Burrillville.
6/4/01 – Primary apple scab season is definitely over. I’m still waiting to find my first apple scab lesion of the season. Check carefully over the next two weeks to see if any scab lesions appear.
– I did see some fresh plum curculio feeding today. Even though it’s been chilly, some plum curculio were active over the weekend. I expect more plum curculio damage – maybe tomorrow if temperatures reach toward 80 degrees. I recommend either a border row spray or a full orchard spray with Imidan or Guthion. I expect that will be the last insecticide needed to control plum curculio this year.
– It is too late to control first generation leafminer with AgriMek or Provado. More than 50% of the mines have advanced to the tissue feeding stage and once advanced, they can’t be controlled with insecticide. If you are finding mines now, the best thing to do is to wait and control the next generation sap feeding mines with Provado.
6/1/01 – At the URI orchard I found several leafminers that have advanced to the tissue feeding stage (when the mines are visible from the upper leaf surface). Check now on the underside of oldest leaves for mines. If you find 13 mines out of 100 fruit cluster leaves consider spraying Agri-Mek as soon as possible. Once leafminers are in the tissue feeding stage they will not be controlled with insecticides, so Agri-Mek must be applied before many have advanced. Agri-Mek must be mixed with something to help it penetrate leaves. Mixing Agri-Mek and oil appears to give the best results. Agri-Mek will also control European red mites.
– Still no fresh plum curculio scars.
– Apple scab lesions appear 9-17 days following an infection period. I expect to find lesions in unsprayed trees any day now.
5/31/01 – There are reports of primary scab spores still waiting to be discharged in New York. If there are still spores in New York (Hudson Valley) there are probably still spores in Rhode Island. Growers should have fungicide coverage going into this weekend. And then primary scab season should really be over.
– Plum curculio have not been very active since 5/19, 5/20. I’ve seen a few fresh scars, but not many. I do expect plum curculio to become active again once it warms up above 70 degrees. Spray Imidan or Guthion before warm weather is anticipated.
– European red mites not controlled prebloom have caused some bronzing in two orchards. Apollo or Savey can be applied now if you find more than 30% of leaves with red mites.
5/25/01 – We received more than 2 inches of rain over the past 4 days, washing off any pesticide that had been applied earlier. Many growers were out spraying today – to recover with fungicide and insecticide. Even though we should be past primary scab infection season, I think it is a good idea to reapply fungicides, especially a fungicide with kick back such as Rubigan, Nova, Procure, Flint or Sovran. These fungicides will also control cedar apple rust. You may have noticed all the orange globby spore structures on cedar trees. During periods of wet weather at this time of the year, spores are released from fungal structures on cedar trees and make their way to apple trees.
– I didn’t find any fresh plum curculio scars today. I don’t think they have been active since last weekend. I do expect them to resume their activity as soon as temperatures return to the 70’s or 80’s. Before the weather gets warm, all growers should have sprayed with Imidan or Guthion. At the URI orchard, we applied the insecticide Avaunt for the petal fall spray. So far this treatment has been working well. I’ll let you know how happy we are with Avaunt at the end of plum curculio season.
– I did see some leaves bronzed by European red mite feeding. Check your leaves now and treat with Apollo, Savey or Pyramite if you find 30% of leaves with red mites. If Apollo or Savey was applied to the trees last year, you should not spray it again this year. Apollo and Savey are very similar pesticides and should be considered the same when thinking about miticide resistance management. To prolong the lives of Apollo and Savey, these chemicals should not be applied to the same blocks two years in a row.
– If you are planning to control leafminers with AgriMek this year, now should be a good time for treatment. AgriMek must be applied with a material to help it penetrate apple leaves. Adding oil to the AgriMek gives the best results. Some growers have not been satisfied with AgriMek when it was mixed with a surfactant. If you are going to apply AgriMek, might as well mix it with oil and not use Captan for at least 10 days.
5/23/01 – We did need the rain , but I’m ready for the sun to shine. This wet weather is probably releasing the last of the primary apple scab spores. If you applied a fungicide recently, you should be all set through this wet period. Those growers that had significant scab last year should apply a fungicide after this rain – to give extra protection against scab.
– Plum curculio were active this past weekend. I found many plum curculio scars on unsprayed trees. Once the temperatures warm up, plum curculio will most likely be active again. Apply Imidan or Guthion before the temperature warms up.
– European red mites are numerous in some orchards that did not apply dormant oil. Mites are much easier to control nopw than they used to be. If 30% of leaves have red mites, consider applying Apollo or Savey. This is assuming you have a crop of apples. If you have a very small crop, it is probably not necessary to spray for red mites.
5/18/01 – I am happy to report that it looks like more fruit out there than I thought there would be. Some orchards still look totally wiped out, but other orchards look better. I’d guess, at this point, that it looks like a 25% crop from a ‘normal’ year. That does not mean that 25% of the fruit are alive. What I see is about 1 fruit/ 2-3 clusters, which I estimate at a 25% crop. It varies incredibly from orchard to orchard and tree to tree. Some later blooming varieties were not hit as hard as others.
– I have not seen any plum curculio damage, but I have heard that one grower saw some injury. I think everyone should have sprayed a petal fall insecticide by now, or should do so very soon. Plum curculio could be active this weekend if temperatures really reach 76 degrees (as forcasted).
– European red mites have started laying eggs. If you don’t have much of a crop then don’t worry about red mites at this time. If you do have a crop you should apply a miticide if 30% of leaves have red mites. Use a miticide that kills eggs such as Savey or Apollo.
– Read the May 11th entre if you have white apple leafhoppers in your orchard. I have found only one orchard with high numbers of white apple leafhopper.
5/16/01 – Looks like we had our first apple scab infection period starting yesterday afternoon and continuing through today. I’m not sure there was enough wetting to cause spores to be released, but we must consider it an infection period.
– I only looked at one orchard in Northern RI today, but I saw much more fruit than I expected to see!!!!! Some fruit with brown interiors are still continuing to grow but many more had green interiors. I’ll check more orchards on Friday, May 18th.
– Saw my first hatched leafminer today.
5/13/01 – I visited many orchards on May 10 & 11 and mostly what I found was not good. Many orchards are close to 100% bud kill from the May 7th freeze. A big question is, what will the fruit be like from those buds that lived? I think we can expect many misshapened fruit due to improper seed development. Only time will tell.
– So what to do? I think everyone should apply a petal fall insecticide spray, even if you think you have nothing left to spray. You may be surprised what survives. After the petal fall spray you can reassess – and decide at that time if you should continue spraying throughout the season. As far as fungicides go, continue spraying fungicides until the end of primary scab season – for about another 10-14 days. After this time, as long as your trees are free from scab you can stop spraying all together if you don’t have a crop to protect.
– If your trees were hit with the freeze, don’t be concerned with mites or leafminers. Light crops can tolerate many more leafminers and mites than trees with a full crop.
– One insect you may be concerned with even if you don’t have a crop is white apple leafhopper. Usually white apple leafhoppers are controlled when Sevin is applied for thinning. Since not much Sevin will be applied, leafhoppers could developed unchecked in many orchards. If leafhopper numbers are high early in the season, extensive leaf damage may affect bud formation. Look now for the small white nymphs on the underside of leaves. I was in an orchard on 5/11 where there were several leafhoppers per leaf. We don’t have a good threshold but 25 nymphs per 100 leaves has been suggested as a threshold. Thiodan or Provado ( 1 oz/ 100 rate) should control leafhoppers well.
– I do not have many European apple sawfly traps set up, but on the ones set up, I have not caught many sawflies. It looks like this is a light sawfly year. This means that it is probably not necessary to rush out and spray an insecticide at petal fall, instead you can wait until the weather is right for plum curculio.
– Plum curculio should have moved into the orchard during all the warm weather we have been experiencing. They will begin to feed and lay eggs when the weather gets damp. Plum curculio like to feed and lay eggs especially during evening showers when the temperature is above 60 degrees. We may have exactly those conditions shortly. It is best to apply an insecticide before plum curculio begin damaging fruit.
5/9/01 – I have not been out to many orchards since the May 7th freeze. I have talked to a few growers and it sounds very bad. I did check buds at Phantom Farms in Cumberland. Here 50-60% of the buds were dead. This surprised me greatly because I have never known them to have any frost damage. I talked to another grower who thinks he is close to 100% kill. I will get to as many growers as possible on Thursday May 10, and report what I find at the Twilight meeting.
– The freeze/frost changes things. You need to assess your orchard before making thinning decisions. To check buds for alive or dead – cut them in half with your finger nail or knife. Dead buds are brown in the middle; live buds are green all the way through.
– I have not found any hatched leafminer eggs yet, but I expect to see them any day. Last year I first found hatched eggs on May 11. If you are spraying for leafminers, Provado should be applied at petal fall or soon after. AgriMek can be applied closer to first cover. If you are using AgriMek, you need to add something to the tank mix to help it penetrate the leaves. Oil works the best.
-Now is a good time to check the orchard for European red mites. Look on the under side of the oldest leaves for the small red mite nymphs. A very good place to check for mites is the leaf clusters that grow directly out of Red Delicious limbs. If you find more than 30% of the leaves with mites, consider applying Apollo or Savey at petal fall or soon after.
– I do not have many European apple sawfly traps set up this year, but the ones I have set up do not have many sawflies on them. Perhaps this is a light year for European apple sawfly.
– Still no apple scab infection period (unless you count the slight one April 12). This weekend could be a major infection period. Unless the forcast changes, all growers should apply a fungicide before the forcasted rain.
5/3/01 – McIntosh trees are blooming in most areas. Many bees were seen visiting flowers today. Looks like a big bloom, and could be a big set with all the bee activity. Be ready to thin at petal fall!
– Saw more hatched European red mites today. It is probably too early to see if you’ll need to treat for mites at petal fall, since all the eggs have not hatched yet. Within the week all the red mite eggs should hatch that are going to hatch, and you can look for red mites at that time.
– I see mite predators in nearly every orchard.
– If we actually get rain 5/4 or 5/5, many mature spores will be discharged and potentially cause an apple scab infection period. I recommend all orchards be protected with a fungicide for the forcasted rain. A fungicide with kick back (Nova, Rubigan, Procure, Sovran, or Flint) can be applied after the rain, but you need to be sure you’ll be able to get in and spray within 96 hours of when the rain starts.
5/1/01 – This warm weather is really pushing everything. McIntosh trees in northern RI are in pink bud stage.
– Found hatched European red mite eggs in one orchard today in northern RI. This means oils applied today or later will not be as effective controlling red mites. Trees located in cooler areas (such as near the coast) probably have a couple of more days before red mite eggs start hatching.
– I’ve still seen only one cluster with rosy apple aphids this year.
– Found 2 European apple sawfly adults on tarnished plant bug traps today. Set up white sticky traps now for EAS. Set traps at head height on the south side of trees, choose border trees or one row in.
4/27/01 – Leafminer adults have been laying eggs. I can easily find eggs in 4 orchards. I plan to check more orchards next week. See the leafminer page for specifics.
-I am convinced that the mites I saw on 4/23/01 are the yellow spider mites. I have seen them in several orchards so far this year, but hopefully they will not become troublesome. Right now they can serve as food for mite predators. I do see Z. mali and A. fallacis in orchards now.
– I’ve only seen one fruit bud cluster with rosy apple aphids this year – and I have looked at many clusters! Check now, especially in Cortlands for this pest. Rosy apple aphids are usually in curling leaves. They are generally brownish-purple with a white cast to them.
– We’ve gone a long time without the chance for an apple scab infection period. When we do get an infection it could be quite severe since so many spores will be discharged.
– No European red mite eggs found hatched yet.
4/24/01 – At URI’s orchard we’ve caught a cummulative average of 93 leafminer adults per trap. I can easily find eggs on the underside of leaves, about 2 eggs per cluster. With the aid of a magnifying glass, the eggs look like small, pale gelatinous blobs.
4/23/01 – What a difference a bit of heat makes! McIntosh trees will be at tight cluster by the end of the day.
– Finding leafminer eggs on the underside of leaves. Found at least 1 egg per cluster in one orchard. I don’t have a good threshold for eggs but I believe that 1 per cluster is far above the threshold. So, maybe 4 eggs per 25 clusters is a reasonable threshold.
– I found a few buds damaged by tarnished plant bug – see a drop of clear liquid on bud. This droplet is oozing plant juice from a tarnished plant bug sting. Check now for damaged buds. I don’t have a threshold for damaged buds – use your own judgement.
– Finding yellow mites in some orchards. I think this looks like the same mite I found in a few orchards last year, but I’m not sure. If it is the same one (identified as the yellow spider mite,Eotetranychus carpina borealis) then I shouldn’t have been able to find it until petal fall. I need to check into this!
4/20/01 – I am so glad to be wrong! There was no infection period 4/18 because it dried out so quickly in the afternoon. It did not stay wet all night like I thought it would.
– Still time to set up red leafminer traps – but don’t wait. We’ve already caught more than 10 per trap at URI’s orchard. We’ve only caught a few in commercial orchards.
– I saw many pear psylla eggs today (more than 10 per bud). If you haven’t applied oil on pearsby now it is probably to late deter pear pyslla egg laying. I did see European red mite eggs on the pear twigs so oil will still be good for controlling red mites on pears.
– Some growers have applied oil and fungicide – you should too!
4/18/01 – I believe this wet weather will cause an apple scab infection period. When the rain started around 3:30pm yesterday, it was about 44 degrees. After a couple of hours it had dropped to 40 degrees and remained there for about 10 hours. The temperature then dropped to around 34 degrees and has been there for about 6 hours. The wet weather will probably continue through the night of 4/18/01. At 34 degrees it takes 48 hours of leaf wetness to cause an infection. But the spores already got a head start at 40 degrees for 10 hours. At 40 degrees only 29 hours are needed to cause an infection. We really need to figure out what the average temperature is during a wet period. Right now the average temperature for this wet period is about 38 degrees. At 38 degrees, 37 hours of leaf wetness are needed to cause an apple scab infection period.
– Caught 42 leafminers on 4 red traps at URI’s orchard (10.5 per trap). The old threshold numbers for apple blotch leafminer are not very useful – but – they are a rough gauge. The old threshold is 8 per trap by tight cluster – which we have exceeded at URI.
4/13/01 – Hudson Valley, NY is reporting 23% mature apple scab ascospores. Scab spore maturity is advanced this year compared with fruit bud development. Economically important scab infections are believed t be possiboe once spore counts reach 15%. Dave Rosenberger from NY has issued a caution to growers that they should be prepared to spray as soon as freen tissue is evident. This is not a year to wait for tight cluster to begin your scab control program! If you had scab last year (as most growers did), you should apply a fungicide now.
4/10/01 – Found 6 leafminers on one trap red and found one tarnished plant bug on one white trap. I’ll bring traps with insects to twilight meeting at Dame’s Farm, 5:30 on April 12.
4/9/01 – Not too much activity in the orchards though buds are breaking. Do not see any leafminers or other important insects.