Rhode Island Apple IPM

2004 - Current Pest Report - Visual Observations

Tree stage for McIntosh (Greenville area)
4/5/04 - Silver tip
4/13/04 - Green tip
4/18/04 - Half inch green
4/26/04 - Tight cluster
5/1/04 - Pink
5/2/04 - King bloom
5/5/04 - Full bloom
5/12/04 - Petal fall

5/13/04 - Petal fall North Kingstown, 5/17/04 - Petal fall Newport County

Visual Observations
8/11/04 - Sorry for the the lack of comments. I still don't have time to write. Do check the apple maggot fly chart. We are still catching lots of apple maggots.
7/20/04 - I'm catching lots of apple maggot flies, particularly in orchards where an apple maggot insecticide has not yet been applied. See chart. If it's been more than 2 weeks since your last insecticide application, it's time to apply one now. Use half rates of Imidan or Guthion.
- I'm finding rose leafhopper in more orchards now. They are present as small nymphs, large nymphs and adults (the ones that fly). The nymphs remain on the underside of leaves until they advance to adults. Leafhoppers are rather easy to control with the proper insecticide. Use Provado, Thiodan, or Sevin. Provado or Thiodan is less harmful to mite predators than Sevin.
- Green apple aphids are nearly gone in all orchards. Thank you aphid predators!
- More orchards have needed mites controlled this year than in the last few years. Miticides have been very effective controlling European red mites and yellow mites. I have not seen any large populations of two-spotted spider mites this year. Growers have been getting good results with Acramite, Zeal and Nexter. If you use Acramite, it is recommended to add a spray adjuvant such as Silwet, Silgard 309, or Kinetic.
- This humid weather is ideal for sooty blotch and fly speck growth. Keep up with your fungicide applications. Topsin M is a good fungicide for controlling fly speck and sooty blotch. Flint and Sovran are also excellent fungicides against these summer diseases. Sovran has a 30 day preharvest interval; Flint has a 14 day preharvest interval.
7/13/04 - I caught a few more apple maggot flies yesterday. We are at the threshold of 2 AMF/trap in 2 out of 10 monitored orchards and close to the threshold in several other orchards. After today's rain would be a good time to apply your first apple maggot fly spray. Use a half rate of Imidan or Guthion.
- I saw many fewer green apple aphids yesterday than I did last week. The predators have really started controlling even the largest infestation. There is a whole assortment of predators out there!
- I found more rose leafhopper nymphs yesterday. They are still rather small and difficult to see. Look on the underside of newer leaves for the small, white nymphs. The nymphs can be controlled now with Provado or Thiodan.
- I also found some more potato leafhoppers. As I said before, potato leafhoppers are only a problem on young trees where you want as much growth as possible. The bright green to yellow nymphs cause the leaves to cup up and the leaves look mottled - large angular sections of a leaf become off colored and then brown. Leaf edges become brown as well. Hopefully potato leafhoppers will be controlled by Imidan or Guthion, but you may need to use Provado, Thiodan or Sevin to control them adequately.
- Yesterday I definately saw some red spots on apples caused by San Jose Scale. It is probably too late now to effectively control San Jose scale this year. It is best to attack them next year with early applications of dormant oil. The best time to apply oil to control San Jose scale is at half inch green.
- Mites have been quite numerous this season. Perhaps the harsh winter killed off too many mite predators causing mite outbreaks this season. The primary pest has been European red mites, but I've also found two spotted spider mites and yellow mites. Many trees have been bronzed by European red mite feeding. It is best to control mites before they cause significant damage. Several miticides have been very effective, but you need to check the label for preharvest intervals. Zeal has a 28 day phi, Nexter has a 25 day phi. Acramite has only a 7 day phi. One grower did use Vendex and did not get satisfactory results.
- Keep to your 2-3 week schedule for fungicides. Since you'll probably be spraying with an insecticide in another 2 weeks for apple maggot, it makes sense to me to use Captan this time and not add the Topsin M. Add Topsin M when you plan on going three weeks between spray applications. And, always use Topsin M on your final spray of the season.
7/10/04 - I caught more apple maggot flies towards the end of the week. We reached the threshold of 2 AMF per trap at 2 orchards. See chart. Many growers have begun spraying half rates of Imidan against AMF.
- Apple blotch leafminer second generation sap feeding mines can now be found on the underside of leaves. If you intend to spray for this pest, consider applying Provado or Calypso now and again in about 10 days.
- Green apple aphids are beginning to disappear in orchards where the predator population has been high.
7/7/04 - I have caught a few apple maggot flies on red sticky spheres in two orchards. Trap captures are below the threshold of 2 AMF per trap. It is still a little early to apply insecticides against AMF. Usually the first insecticide is not needed until around July 15-20, but I'll let you know what I find on the traps. When you do spray for AMF, half rates of Imidan work well.
- I started finding potato leafhopper adults and tiny nymphs this past week. I distinguish potato leafhopper nymphs from other leafhopper nymphs by their color and speed. The potato leafhoppers are quite green while the white apple leafhoppers and rose leafhopper nymphs are white or cream colored. Also, potato leafhopper nymphs move very quickly when touched and disturbed. Potato leafhoppers should be controlled on young trees because potato leafhopper feeding stunts tree growth. On mature trees, we don't worry about tree growth being stunted (we like stunted growth!)
- I've also started finding rose leafhopper nymphs in a few orchards. A good time to spray for rose leafhopper will probably be aroung July 15. We don't have a good threshold for leafhopper spraying - but use a threshold of 25 nymphs per 100 leaves. Rose leafhoppers will not be controlled with Imidan or Guthion. It is best to use Provado, Calypso or Thiodan. Sevin also controls leafhoppers but is more harmful to predatory mites.
6/28/04 - European red mites are building in some orchards. Growers have had excellent results using miticides this year. If your trees exceed the threshold of 2.5 mites per leaf or more than 54% of leaves have mites, consider applying Zeal, Nexter, or Acramite.
- Leafminer adults are emerging now. Some have probably started laying eggs for the second generation. If you find more than 13 mines out of 100 fruit cluster leaves, consider applying Provado or Calypso against the second generation mines. The timing for this spray will probably be around July 10 and then again about July 17.
- I still have not seen any potato leafhoppers this season. Be sure to check young trees for leafhoppers. Check new growth for the small, pale leafhoppers and spray young trees if you find them. Generally potato leafhoppers can be controlled with Imidan, but sometimes it is necessary to spray Thiodan, Provado or Sevin.
- I see many white apple leafhoppers flying around in some orchards. The population can be reduced by spraying Thiodan, Provado, or Sevin. If there aren't very many, you can wait until August and see if the second generation needs to be controlled.
- I don't see any additional rose leafhoppers yet. Perhaps there won't be as many this year as other years. We'll see.
- Green apple aphids have had a big week. I see plenty of green apple aphids especially in trees that were pruned heavily. If you have lots of aphids, my advise to you is 'wait a week'. Often in a week most of the aphids can be consumed by predators.
6/21/04 - Really there is nothing new to report. Continue to check for European red mites and two-spotted spider mites. I have not found any two spotted mite problems this season. I have found several orchards that required a miticide application to control red mites.
- I have not found any potato leafhoppers yet this season. Be sure to check your young trees for leafhoppers. Check the newest few leaves on terminal shoots. This is usually where the leafhoppers appear. They are not a problem on mature trees, but they do stunt the growth of young trees.
- Rose leafhoppers continue to migrate onto apple trees, but are not a problem at this time. If a insecticide application is necessary, it should be applied in mid July.
- I see more green apple aphids, but also more aphid predators. I don't think green apple aphids will require spraying in any orchard.
- Starting in the end of June or early July there are more spores of both sooty blotch and fly speck around. Before late June these summer diseases are not much of a threat. After late June you need to keep your trees protected from summer diseases. This can be accomplished by applying half rates of Captan every two weeks or half rates of Captan plus Topsin M every 3 weeks.
6/15/04 - I didn't get to finish writing my observations from yesterday:
For those of you whose trees have San Jose Scale, Orchard Radar predicts San Jose Scale crawlers should start emerging June 17 in Greenville, June 19 in North Kingstown, and June 21 in Newport County. If you need to control San Jose Scale, an insecticide should be applied when crawlers first emerge and then again 7-10 days later. Esteem works very well to control crawlers. Imidan or Guthion will also control the crawlers, but probably not as well as the Esteem.
- Green apple aphids are present in most orchards and so are aphid predators. In nearly all situations, the natural aphid predators will control green apple aphid, so an insecticide treatment is not needed.
6/14/04 - It's a nice time of year in the orchard - you can usually spread out the time between spray applications. Insecticides are generally not needed for several weeks, now that plum curculio season is finished. As long as apple scab is under control you can go 2-3 weeks between sprays. Spray Captan every 2 weeks or go 3 weeks if you spray Captan and Topsin M.
- There are a few pests to watch for. European red mites and two spotted spider mites are always a concern and need to be monitored. From now through mid-July, the spray threshold for red mites is 2.5 mites per leaf or 54% of leaves with mites. If your trees reach this threshold apply a miticide. Use Nexter (new formulation of Pyramite) or try Zeal (a new miticide). In the past, we've had good results controlling mites by mixing Vendex with Tactic (a spreader-sticker). Vendex plus Tactic is probably less expensive than other miticides.
- Another possible pest now is rose leafhopper. I just started seeing rose leafhopper on apple trees today. These leafhoppers spend the first part of the season on rose and then migrate to apples this time of year. Nothing should be done about rose leafhoppers now. If they do become a problem, you can spray the nymphs later in July.
- Some orchards may still have some white apple leafhopper. These are present now as large nymphs or adults (the adults are the ones flying around). If you do have many white apple leafhoppers now and you see the white stippling damage caused by leafhopper feeding, you can apply Provado, Thiodan or Sevin to control them. The threshold is 25 nymphs per 100 leaves.
6/9/04 - This hot weather is bringing out the last of the plum curculio. Orchards that were sprayed with insecticides in the last 10 days should be protected through this hot weather. If you find new scars, consider applying a border spray of insecticide.
- This hot weather is not expected to last, but I'm sure it's speeding up European red mite egg hatch. At this time of year, probably any miticide will work quite well: Apollo, Savey, Pyramite (now called Nexter). The threshold until the middle of June is 1 mite per leaf or 30% of leaves with mites. From June 15 to July 15 the threshold is 2.5 mites per leaf or 54% of leaves with red mites.
6/3/04 - I found some fruit scab today, first I've seen this season.
- I have found caterpillar feeding damage in a few orchards. The caterpillars are taking big bites, similar to green fruit worm injury. I believe insect is the winter moth, Operophtera brumata, which I believe is a new insect for Rhode Island. It is originally from Europe and has been in Canada for many years. This spring it has been reported in coastal Massachusetts orchards. Insecticides applied against plum curculio should control the green winter moth caterpillars. I'll work on getting a picture on this site.
- And yesterday I said it was too late to spray for first generation leafminer, and then I was in an orchard today where all the mines were sap feeding mines. The grower only has a day or two if he wants to treat these trees with Provado or AgriMek, but it wasn't too late now. Once more than 10% of mines have advanced to the tissue feeding stage (when they are visible from the upper leaf surface) it is too late to control the mines.
- I wrote a lot yesterday - Read that!
6/2/04 - I'm finding more apple scab in orchards that I thought were free from scab. Be sure to check leaves closely. New lesions can be quite faint and difficult to see. A full rate of Captan should be applied to trees with more than just a tiny bit of scab.
- I'm surprised how active plum curculio have been during this cool weather. I've seen many fresh egg laying scars, especially in orchards not well protected with insecticides. Orchard Radar predicts the final plum curculio spray is needed June 1 or later in the Greenville area; June 5 or later in North Kingstown as well as Newport and Little Compton. Plum curculio migration is expected to continue for another 2 weeks after that, but provided we don't get more than 2 inches of rain, the insecticide should control through the end of plum curculio migration.
- If plum curculios aren't killed (let's say you only apply one insecticide at petal fall) they can continue to feed and lay eggs well into July. And when larger fruit are attacked by plum curculio, the tend to stay on the trees into harvest. Small fruit attacked by plum curculio tend to fall off.
- It is probably too late to control first generation leafminer mines now. If you see that you have too many mines on your leaves (more than 13 mines out of 100 fruit cluster leaves), you can wait and try to control the second generation mines. It is more difficult to control the second generation and probably would require two applications of Provado, about 7 days apart. If sprays are needed for second generation leafminer control the first application of Provado would be applied around mid July. The threshold for second generation mines is 1 mine per leaf. If you exceeded the threshold for first generation, you can expect you'll exceed the threshold for the second generation.
- I've seen very few white apple leafhoppers this spring, even on trees not treated with Sevin for thinning.
-Green apple aphids are starting to appear on new shoots. In nearly every case, natural predators control aphids beautifully - No insecticide needed!
- Once you have applied your final plum curculio spray, it's a good time to relax on spraying. Hopefully you won't need another insecticide application until it's time to spray for apple maggot fly. Usually an insecticide isn't needed for apple maggot fly until the first or second week of July. So, along with your final plum curculio spray, include Topsin M with the Captan so you can go three weeks before spraying again.
- According to Orchard Radar, we can expect to start seeing San Jose Scale crawlers on July 18.

5/30/04 - Cool weather has slowed down plum curculio migration. Orchard Radar now predict that the last insecticide against plum curculio can be applied no earlier than June 2 in the Greenville area. In North Kingstown, the predicted date for final plum curculio spray is June 3, and the Newport area date is June 5. If your insecticide is applied at these dates or later, your fruit should be protected through the end of plum curculio migration. If you have questions about this, please call me at 874-2750.
5/24/04 - We are past primary apple scab season in all but the latest orchards in the state. If your trees are past petal fall, primary scab season is most likely over in your orchard. Continue to monitor your leaves and fruit for lesions. Apply full rates of Captan if you find even a little bit of scab. Secondary scab spreads very easily. It does not take very many hours of leaf wetness to cause an infection for secondary scab.
- I've seen a lot of plum curculio damage over the last few days. In areas where the temperature exceeded 70 degrees and was humid, the plum curculio have been very active. We are nearing the end of plum curculio migration season, but we are not there yet. At this point, Orchard Radar predicts that a final plum curculio spray needs to be applied on May 29 or later in Greenville, May 31 or later in North Kingstown, June 3 or later in Newport County. This prediction is based on when plum curculio are expected to finish migrating (based on degree day models) and how long full rates of Imidan are expected to protect the fruit. So, insecticide applications are still needed against plum curculio.
- I have seen numerous winding trails caused by European apple sawflies. I find them in orchards that did not receive an insecticide right at petal fall - some growers waited up to a week after petal fall. Spraying insecticdes over the next week will kill the sawfly larvae after they leave one fruit and before they enter another fruit. In unsprayed trees, European apple sawfly can attack nearly every fruit. They are rarely a problem in sprayed settings.
- I found one leafminer that had advanced to the tissue feeding stage. This is when the mine is visible from the upper leaf surface. If you are planning to spray to control leafminer mines, now is the time to do it. Use Provado, AgriMek or Calypso.
- Some growers have applied miticides to control European red mites. In each situation the mites have been well controlled with Apollo or Pyramite. Through the middle of June the threshold for European red mite is 30% of leaves with mites.
5/20/04 - This warm, humid weather is perfect for plum curculio egg laying. All fruit trees should be protected now against plum curculio. Use Imidan, Guthion, or Avaunt at full rates.
- The rain of May 18 probably released the last of the overwintering ascospores for the season in the Greenville area. Orchards along the coast are further behind, and still in primary apple scab season. After spraying this week, you can probably switch to spraying a fungicide every 2 weeks, assuming you've had good fungicide coverage throughout the season. Be sure to scout your trees now for lesions and spray with full rates of Captan if you find more than just a very few lesions. I know this is sounds very subjective - but it is - and it's better to be cautious when dealing with scab. In addition to the Captan, you can add Sovran, Flint, Rubigan, or Nova.
-Leafminer sap feeding mines are just becoming visible on the underside of leaves. Now is the time to treat if you need to control leafminer. Use Provado, Calypso, or AgriMek.

5/17/04 - We are nearly at the end of primary scab season. Apply a fungicide this week and then you can probably switch to spraying a fungicide every two weeks. If you do have scab in your orchard now, apply full rates of Captan 5-7 days apart. You can also add Rubigan, Nova, Sovran or Flint to the Captan to help burn out scab lesions.
- I found plum curculio egg laying scars in three orchards today. It is time to have your trees protected with Imidan, Guthion or Avaunt.
-Leafminer. Leafminer adults are still active in orchards laying eggs. Eggs laid earlier in the season have started hatching. If you intend to spray against sap feeding mines, plan on spraying AgriMek at petal fall or Provado or Calypso about 10 days after petal fall, at first cover. (AgriMek must be applied with a penetrant to get the insecticide into the leaves. Use oil or LI 700.) We had a lot of good weather this spring, allowing leafminers to lay many eggs. This could be a big year for leafminers!
- I'm finding many orchards with European red mite populations above the threshold of 30% of leaves with mites. If you are in this situation, consider applying Apollo, Savey, Danitol or AgriMek. AgriMek would be a good choice if you also needed to control leafminers.
- Everyone's set looks very heavy! Thin aggressively! Check out Orchard Radar for help on thinning. There are links to the three Rhode Island Orchar Radar sites on the front page of this Apple IPM website.
5/13/04 - I'm finding apple scab lesions in more orchards. The lesions I found yesterday were much easier to see than they were on May 10. The heat has made them darker and more visible. To look for lesions, stand under a McIntosh tree or a tree where it is difficult to spray. Look up into the canopy to search for lesions. If you find any lesions, consider applying a full rate of Captan now and again in 5-7 days. You can add Rubigan, Nova, Sovran or Flint to the Captan, but realize that this approach strongly encourages scab resistance to these chemicals.
- I am finding European red mites in more orchards. I think many growers could not make adequate oil applications this spring. It is much better to control mites earlier than later. Consider applying a miticide soon if 30% of leaves have mites. Use Apollo, Savey, Danitol, or AgriMek. Danitol and AgriMek will also control leafminers, but Danitol is a synthetic pyrethroid and we discourage growers from using synthetic pyrethroids. If you used a miticide last year, use a different one this year. And remember, Apollo and Savey are very similar chemicals, so if you used either one last year, don't use either one this year.
- Petal fall has occurred in many orchards. Include Imidan in your petal fall spray to control plum curculio and European apple sawfly. Sawflies have been busy laying eggs during bloom. I don't have many traps set up, but I caught sawflies in every orchard where I do have traps.
- I am recording telephone messages each week, usually on Mondays. The number is 949-1456.

5/10/04 - We had another apple scab infection period on Mother's Day, May 9th. This was a very important infection period because many spores matured during the week and weren't released until the rain of May 9th. IF you had sprayed a fungicide since Wednesday, May 5th, your trees should have been well protected. If your last fungicide application was applied before May 5th, consider applying a fungicide with kickback such as Rubigan, Nova, Sovran, or Flint.
- I did find my first apple scab lesions fo the season today. I did not find them on the oldest leaves, but instead on the middle aged leaves. The lesions were very small and just looked like gray smudges. Look now for lesions in your trees. If you find them, apply a full rate of Captan now and again in 5-7 days. The predicted hot weather should help burn out scab lesions.
- Check your trees now for European red mites. Check the underside of oldest leaves for the small, red mites. If 30% of leaves have red mites, consider applying a miticide at petal fall. I have seen quite a few mites in some orchards.
-TWILIGHT MEETING Wednesday! Click here for directions.

5/6/04 - That was a huge infection period on Sunday May 2 through Tuesday morning May 4th. Hopefully most of your trees were protected with a fungicide before the wet weather. If not, apply full rates of Rubigan, Nova, Sovran or Flint as soon as possible.
- I found my first hatched European red mite today. I found it at URI's East Farm where the trees are barely in pink now. I expect ERM started hatching in the Greenville area several days ago. It is too late to apply dormant oil to control red mites, unless some areas are still at tight cluster. (Perhaps Newport and Little Compton are still in tight cluster.)
-More tarnished plant bugs were caught over this past week, but no location is above the spray threshold.

4/30/04 - McIntosh trees will probably be at pink on May 1. This warm weather has really moved the trees forward - and apple scab as well. The next wetting period will release a HUGH number of ascospores, making the next period of wet weather extremely important. Either spray before the next forcasted rain (5/2 afternoon) or come in immediately afterwards with a kickback fungicide (Rubigan, Nova, Sovran, or Flint).
- At this point, reduce oil rates to 1 gallon oil per 100 gallons of water.

4/29/04 - We did have a major apple scab infection period from Sunday night, 4/25 through Tuesday morning 4/27. Approximately 20% of overwintering spores should have been matured as discharged as of 4/27. We are now entering the accelerated phase of apple scab. Now is the time to really concentrate your efforts to protect your trees from scab. If you are not protected from scab with a contact fungicide before an infection period, be sure to use Rubigan, Nova, Flint, or Sovran soon after an infection period.
- Continue to add oil to your sprays. Reduce the amount of oil to 1-2 gallons of oil per 100 gallons of water. Don't apply oil if a frost is expected within 48 hours of application.

4/23/04 - Last week there was a major early season apple scab infection period. Today's wet weather may or may not be an infection period. All growers should have applied a fungicide by now! If not, you could run into serious problems with scab.
- I understand there are problems buying Syllit this year. Growers should depend on other protectant fungicides such as Manzate or Polyram. Manzate or Polyram can be used at the full rate through bloom. If you choose to use only a half rate you can extend your use until 77 days before harvest (around 2nd cover).
- Leafminers are above threshold in about half of blocks monitored with red sticky spheres. This is usually how it is every year. Blocks with large, old trees are most susceptible to high leafminer populations. Leafminer can be controlled at pink with a synthetic pyrethroid, but it is recommended you wait until after bloom and use Agrimek, Provado, or Calypso. Calypso has the added advantage of also controlling plum curculio.
-I am catching tarnished plant bugs on white sticky traps, but not in high numbers. No orchard is near the threshold.

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