In this issue
Tree fruit news
§ 2005 TNRC trapline data -- San Jose scale
§
Making codling moth mating disruption work in
§ Pre-harvest control of third generation codling moth
§ Apple maturity testing at MSU
Small fruit news
§ Control of Phomopsis twig blight and canker in blueberries
Other news
§ TNRC Field Day reminder – September 27
§ Regional reports
§ Dryness intensifies
Even in a good year, codling moth (CM) is a thorn in the side of apple growers everywhere. Unfortunately, growers have seen even more in the way of reduced pack-outs due to CM damage, and load rejections due to the detection of wormy fruit in the past few years, as traditional management programs based on applications of organophosphorous (OP) insecticides fail to gain control of CM.
Resistance bioassays conducted by the Tree Fruit Entomology lab (Larry Gut, Peter McGhee, and Mike Haas) at MSU have revealed high levels of CM resistance to azinphosmethyl in most production regions, with levels similar to those reported for populations in western United States fruit orchards where CM control failures have been attributed to azinphosmethyl resistance. The development of CM resistance to azinphosmethyl means that controlling CM into the future may require the use of some innovative management programs to stay ahead of this perennial troublemaker.
In an attempt to explore viable control options, a cooperative effort between apple producers and MSU researchers and Extension personnel to establish an areawide CM management program began in 2004 in the Fruit Ridge area, north of
Area-wide management programs have been conducted in many fruit production regions around the world.
Codling moth mating disruption was first introduced to
Another impediment is that mating disruption programs are information intensive. Regular and accurate determination of the pest’s density and biological activity is necessary to decide if and when supplemental controls need to be applied. This means maintaining a thorough, weekly monitoring program using pheromone-baited traps along with visual inspection for damage throughout the disrupted area.
A third concern with the adoption of mating disruption is that researchers who have been working to implement pheromone disruption as a control tool for use by growers have recognized that this control strategy works best where it is deployed over large, contiguous plantings, rather than in small plots surrounded by other orchards. This approach makes it more difficult for male moths to move to pheromone-free air and locate mates, while minimizing the movement of mated females from orchards not treated with pheromone into the pheromone treated blocks.
The combination of large contiguous apple plantings and high levels of azinphosmethyl resistance, made the Fruit Ridge area a good candidate for testing the area-wide management approach under
Mating disruption products are applied by growers prior to first adult emergence in the spring. Product selection is left up to the grower and their pest management consultant, and is purchased by the individual grower. The AW project also entails incorporating other new controls for codling moth into the growers IPM program, most notably codling moth granulosis virus and the selective insecticides Calypso™, Rimon™, and Assail™, while working with growers to optimize timing and coverage of materials in their spray program. Optimal use of the virus is against young larvae before they penetrate the fruit. The best way to target young larvae is to have the virus present on the surface of the eggs when they begin to hatch. Hatching CM larvae will ingest the virus as they consume their eggshells.
The MSU project team set up a grid of over 300 pheromone traps within the 800 acre 2004 AW project and monitored codling moth catches on a weekly basis. The monitoring grid grew to 960 traps placed throughout the three AW project regions in 2005. This information is being used to evaluate the impact of the pheromone treatments, and it is provided to growers and crop consultants to help in making management decisions. Orchards are also visually inspected for the presence of CM injured fruit throughout the first and second generations in an effort to minimize the risk of incurring a major control failure.
In addition to trap monitoring, the project team deployed cardboard tree bands for evaluation of Granulosis virus treatments on CM larvae collected in the bands in 18 blocks (both AW farms and farms outside the AW for comparative measure) for first and second generation CM. Virus products were used on approximately one-third of all project acreage. Preliminary analysis of first generation larvae in bands in 2005 indicates lowered CM larval densities in blocks treated with Granulosis virus.
Growers and consultants are apprised of project results through an information kiosk that was established at the “Peach Ridge Orchard Supply” store in
The area-wide project team and growers hope that a variety of tactics and new approaches in implementation, such as area-wide cooperation among growers, will provide solutions for the ever-increasing pressure from the key insect pests of apple. The long-term goal of this area-wide effort is to bring codling moth numbers down over the next few years, and to sustain codling moth populations at very low levels through the continual use of pheromone-based mating disruption and judicious use of companion insecticide sprays. Previous area-wide programs have revealed that the overall sustainable benefit of regional mating disruption programs occurs gradually, needing 2, 3 or more years to come to fruition.
The legacy goal of this program is that growers will recognize the benefit of working cooperatively to manage codling moth and that mating disruption deployed on a regional basis is a core tactic for controlling this pest well into the future. The success of this program could lead to more cooperative pest management in the form of area-wide control of obliquebanded leafroller and oriental fruit moth. Several newly developed mating disruption dispensers target more than one species at a time by combining different pheromones into one product.
Adopting an area-wide approach to manage these pests may be one of the best ways for
This project is supported through funding by various sources including the USDA, the EPA, American Farmland Trust, Gerber Products Company, Pacific Biocontrol Corporation, and
Important considerations for third generation codling moth (CM) control include predicted harvest dates for different cultivars and associated pre-harvest (PHI) and re-entry intervals (REI) for the different control materials (Table 1). Options for controlling CM include conventional broad-spectrum insecticides, like the organophosphate (OP) compounds, Guthion and Imidan, and a number of pyrethroid insecticides. These materials are applied primarily targeting CM egg hatch, beginning at 250 GDD post biofix. Apple growers should be aware that resistance to the OP compounds has been detected in
Compound Trade Name |
Life-stage Activity |
Total Allowable product/acre/yr* |
Pre-Harvest Interval* |
Re-Entry Interval* |
Guthion** |
Eggs, Larvae, Adults |
8 lbs |
14 day |
14 day |
Danitol |
Eggs, Larvae, Adults |
42.6 oz |
14 day |
24 hr |
Rimon |
Eggs, Larvae |
150 oz |
14 day |
12 hr |
Intrepid |
Eggs, Larvae |
64 oz |
14 day |
4 hr |
Imidan |
Eggs, Larvae, Adults |
30 lbs |
7 day |
24 hr |
SpinTor |
Eggs, Larvae |
29 oz |
7 day |
12 hr |
Assail |
Eggs, Larvae, Adults |
13.5 oz |
7 day |
12 hr |
Clutch |
Eggs, Larvae, Adults |
6.4 oz |
7 day |
12 hr |
Sevin |
Adult, Larvae |
15 lbs ai |
3 day |
12 hr |
Granulosis virus |
Larvae |
Varies by product |
4 hr |
4 hr |
* for apples only; Gerber Products Co. restrictions may differ
** 21 day PHI if more than 2 lb rate of Guthion 50W
For many years MSU has tested apple maturity as harvest approaches to allow growers and shippers to make informed decisions on harvest dates and marketing for the many apple varieties grown in
Apples are sampled for flesh firmness, starch content or the conversion of starch to sugar, soluble solids or sweetness of the juice and ethylene content of the fruit. The results of these tests are disseminated by agent Code-A-Phones, fax or web page so that growers can keep abreast of the regional and state conditions during harvest. Several educators in the past have posted their results on the Internet. This year, the Fruit Area of Expertise team will link all the posted reports and also related source material on an apple maturity page on the MSU Fruit Team web site at http://web1.msue.msu.edu/fruit/. This central location will allow growers to access Apple maturity and ripeness information at on central location. Regional Apple maturity information can still be accessed by regional Code-A-Phones and in some cases Fax Updates for growers without Internet access.
Boron deficiencies occur most often in light sandy soils. Boron deficiencies can cause poor growth, dieback, corking or cracking of the fruit and poor fruit set. Boron is not very soluble in water. Even through the fruit crops only need a small amount of boron, in drought years we often see boron deficiency symptoms. Typical ground applications are of 1 to 1.5 pounds per acre for apples and pears and 0.5 to 1.0 pounds for cherries. Peaches normally only receive 0.5 pounds. At this late date, ground applications will not allow the trees to absorb enough boron to do any good in time for fruit set next spring, even if we had adequate soil moisture.
Foliar application of boron allows growers to get boron into the tree and into next year’s flower buds where it will do the most good. Boron needs to be put on while the leaves are still active. Normally we do not advise applying born unless leaf samples indicate that levels are deficient, but late season foliar sprays often result in increased fruit set without increasing foliar boron levels. Use no more that 0.5 pounds of actual Boron per acre for these late season sprays. This amount of Boron should allow your trees to produce healthy flowers and pollen for bloom next spring.
Throughout the 2005 season, cane dieback was observed in numerous blueberry fields, including in Bluecrop, Duke and
The Phomopsis cane canker and twig blight fungus can infect young canes and twigs directly if they are wet for a long period and also enters the canes through wounds caused by harvesting equipment or pruning activities. The fungus overwinters in infected canes and twigs and produced spores from April to September, with a peak in May to June. An aggressive program to combat Phomopsis would look something like this:
1) Prune out dead and diseased canes and twigs, including green canes with lesions. If the bushes look very bad, mow off everything, and let new canes come up. Use fungicides to protect new canes from infection.
2) Destroy diseased canes. Ideally, they should be removed from the field and burned. However, because of the labor involved, most growers just bushhog the canes and leave the remnants lying in the row middle. This is probably not a big concern, because Phomopsis spores are dispersed by rain splash and consequently won't go very far (usually within a few feet of the source). It may only be a problem if the canes are lying close to or are left in the bush. While the canes are a potential source of spores, if they break down quickly, the Phomopsis fungus will also be destroyed. So the better they are chopped up and in contact with the soil, the quicker Phomopsis will be gone.
3) Prevent canes from getting herbicide burns or other wounds (e.g., from a harvester or other equipment) which may predispose them to infection. Irrigate during dry periods (including in the fall) to reduce plant stress.
4) Protect canes and twigs with Topsin M+ Captan or Topsin M+ Ziram on a fairly regular schedule (e.g., a spray every two weeks) from early pink bud through pea-size fruit. Indar (fenbuconazole) is also very good against Phomopsis, so if you are spraying Indar for mummy berry anyway, you are also covered for Phomopsis. Bravo will also work, but can't be sprayed after bloom. Other effective products are Pristine and Cabrio. In years with a warm and wet early fall, a post-harvest spray may be useful to protect newly developed buds and young canes as well as older canes wounded by harvesting from infection. Previous research has shown spore activity to cease in early September, so sprays should not be needed after mid September.
5) Lime sulfur can be put on in the fall after leaf drop and/or as a delayed dormant application in the spring. This will reduce inoculum and fewer fungicide sprays may be needed the following season. We are currently investigating liquid sulfur and copper as dormant sprays. These products are much less expensive than lime sulfur.
6) Don’t feel discouraged if you do not start seeing results immediately. One needs to keep up this program for at least two years, because it may take a year for existing infections to show. A hard winter with lots of winter injury may also make the bushes appear in worse shape.
7) There are other canker diseases out there, including Fusicoccum canker (in northern
We will be having a research field day at the Trevor Nichols Research Complex on Tuesday, September 27 From
See our web page for directions: http://www.maes.msu.edu/tnrc/
Last two week’s weather was warm and dry with highs near 80 and lows near 60. There was rain in the northern and eastern counties of the region on August 27, but most areas received less than a tenth of an inch Allegan and
GDD totals for March 1 through September 4 |
Grapes |
|||
Location |
GDD 42 |
GDD 45 |
GDD 50 |
GDD 50 |
3724 |
3280 |
2583 |
2582 |
|
3815 |
3363 |
2632 |
2609 |
|
3506 |
3065 |
2355 |
2336 |
|
3763 |
3319 |
2621 |
2598 |
|
3552 |
3090 |
2409 |
2390 |
|
Trap catches are variable from site to site. Generally, Oriental fruit moth numbers are up. Codling moth numbers are low at some sites and up in others. Redbanded leafroller trap catches are falling from last weeks high. Obliquebanded leafroller trap catches are low. Apple maggot and blueberry maggot numbers are low. Japanese Beetles are scarce.
Peach harvest continues with Autumn Star and Harcrest. Oriental fruit moth trap catches are high. I think the fourth generation is flying. Brown rot is showing up here and there. San Jose scale has been reported on a lot of peaches. Growers should consider dormant oil treatments to reduce this pest during the winter season.
In apples, we are harvesting Zestar, Gala, Macintosh and Jonathan. Golden Delicous harvest for processing will begin this week in some orchards. Apple Maturity Updates will begin this week. See the article in this week’s Fruit CAT Alert. There is a very heavy flight of European corn borer. Growers who have a problem with this pest need to maintain excellent coverage. Trap catches for codling moth are varied and not as high as I expected with a third generation of codling moth. Oriental fruit moth trap catches are high indicating the flight of a fourth generation. Growers need to protect against Oriental fruit moth and codling moth for several more weeks. White apple leafhopper nymphs are easy to find. Examine 50 leaves from 10 different trees and treat if the average is more than one nymph per leaf. Trap catch for Obliquebanded leafroller is low. Redbanded leafroller flight is heavy. We caught few apple maggots last week.
Blueberry harvest is finished.
In grapes,
Fall raspberry harvest continues. With heavy dews every morning, growers need to protect against fruit rots especially gray mold and botrytis. Neem Oil materials would be good insect repellent materials to use to prevent or reduce Asian multicolored lady beetles and late Japanese beetles from feeding on the fruit.
The real weather story is the continued dry soil conditions. There are signs of drought stress in strawberries, raspberries and blueberries. Fruit size in apples continues to be very good despite the drought conditions. A few lucky growers have received between 0.5 and one inch of rain in the form of small isolated thundershowers over the last two weeks. Most have had some minor thundershowers that have simply settled the dust more than provided additional soil moisture. Continued warm weather has still pushed our season much ahead of normal. Our season is now running about eight to 12 days ahead of normal in terms of degree day totals.
Apple harvest is gearing up quickly. Many growers are spot picking early maturing McIntosh and Gala strains. Honeycrisp is being spot picked. Peach harvest is almost complete with the exception of a few very late season varieties. Fall red raspberry harvest continues, and blueberry harvest has wrapped up. Grape harvest is underway for some of the early maturing varieties.
GDD totals for March 1 to September 6 |
|||
Location |
GDD42 |
GDD45 |
GDD50 |
3605 |
3168 |
2493 |
|
Romeo |
3677 |
3231 |
2554 |
3633 |
3192 |
2520 |
|
Apples continue to size very well despite the dry or even drought conditions. I feel that this adequate fruit sizing is the result of above normal moisture supplies in the soil as we started the season. Most apple varieties are now 3.5 inches in diameter. Oriental fruit moth trap catches continue to be high. It has been a bit of a difficult insect to track this year due to the prolonged flight times within the generation. I’m also seeing some good size oriental fruit moth larvae. Codling moth trap catches are low. I am waiting for the third generation adult flight to begin. This should happen within the next few days. I encourage growers to check codling moth traps every few days to determine the start of the third generation flight and biofix. By doing so they can pinpoint control measures. I remind growers to consult the well-written article on third generation codling moth in the last issue of CAT Alerts (August 23, 2005). Apple maggot continues to fly, mostly triggered by rain or moisture events. Apple maggot flight this late in the season rarely causes a problem with infected fruit. Trap catches have been low on both yellow boards and red sticky traps for apple maggot over the last two weeks. Most other insects are under control.
Light amounts of sooty blotch and flyspeck continue to be seen. Necrotic leaf blotch infected foliage continues to turn yellow and drop on Golden Delicious and its strains. Bacterial spot continues to show up in light amount on Crispin.
Pears continue to size nicely. Most people are now beginning to harvest
Peach harvest has pretty much wrapped up with the exception of a few very late season varieties. The only new problem to report is light amounts of San Jose scale in a few blocks. This is a bit of an unusual pest problem to find on peaches. Now is a good time to access damage and make plans for the 2006 growing season as this needs to be controlled very early in the year. Most peach blocks continue to show signs of bacterial spot, as well as X-disease.
Sweet and tart cherry blocks continue to show signs of yellowing leaves as a result of leaf spot disease.
Strawberries continue to rebound from the renovation process. Potato leafhopper populations are now under control in most plantings as are twospotted spider mites.
Raspberry harvest for fall red raspberries continues. Heritage has just begun harvest over the last two days. Multi colored Asian lady beetles are showing up in higher numbers in fall raspberries. I’m starting to see a few signs of spur blight and leaf spot, primarily in summer red raspberries. Now is a good time to be spotting for both of these diseases.
Blueberry harvest is now wrapped up. While many berry growers have left some berries on later season varieties, the quality of these last berries has now diminished to a point where it is not practical for picking.
Grape harvest is now underway for some of the seedless and early maturing varieties. We are weeks away from
According to 30-year averages from the
Weather station |
GDD42 |
GDD50 |
West Olive |
3725 |
2622 |
3780 |
2576 |
Harvest is complete for Gingergolds. There are a few Paula Reds hanging, waiting for more color. Some Empires have been harvested for taffy apples. Honeycrisp are starting to show maturity on some fruits and they taste good – a few Honeycrisp have been harvested for retail markets. Macs and Empires are pushing off some trees and some early harvest has begun. Gala: a few of the redder strains are being harvested, but maturity is not proving to be as advanced as we earlier thought.
Retain applications should be timed for 30 days prior to anticipated harvest date to have the most effect. Varieties to consider for Retain applications are Golden Delicious and Red Delicious. Applications need to be made right away. On Ida Reds, Retain should go on this week and for Romes, Retain should go on over this coming weekend.
We have accumulated 987 GDD50 from my second generation biofix for codling moth indicating that second generation egg hatch should be over. Trap numbers should have been down to zeros over the past week or so, but numbers have continued to be trapped. This is a third generation of codling moth and growers will have to take this very seriously this year – we will have a full third generation. I set a third biofix for this next generation on August 23. From this date, we’ve accumulated 225 GDD50 – indicating that early egg hatch could be starting for this third generation of codling moth, and cover sprays continue to be important for at least another three to four weeks, depending on the weather.
It will be very important this fall to follow your trap numbers to let you know if cover sprays are still needed. A rule of thumb is that if you catch over five moths per trap in a week, you need to stay covered for at least two weeks after that trap catch to avoid stings. This would be true for a third generation as well. Listen to your scouts and consultants to determine if you need to stay covered up for codling moth – it will be important this year.
It will also be important to watch the PHI of the materials you choose for late season pest control at this time. Gerber PHI’s are very different from the labeled PHI, so be sure to check the Gerber list before choosing a material if you’re marketing that way.
We’ve accumulated 617 GDD42 since the second generation biofix for obliquebanded leafroller on August 12. OBLR egg hatch should be well underway and controls should be considered right now for blocks that have had high leafroller numbers earlier this season. There are larvae present in normal numbers right now. It will be important for scouts and consultants to watch closely for OBLR larvae.
Third generation trap numbers of Oriental fruit moth were up slightly last week. We should be nearing the end of egg hatch for this year, but cover sprays should still be considered for late peach varieties right now as well as apples that have had stings from OFM in the past. I expect egg hatch to be over in 10 to 14 days for OFM.
Continue to monitor for apple maggot flight and spray accordingly. I have caught no apple maggot in the past two weeks, but if we do get some rain over the next day or two, they could still fly.
In most places around west central
In comparison with the past year, the 2005 harvest has been shortened by almost a month. In 2004 the harvest of Elliott extended into the first week of October. As a result of the summer drought and sanitary problems the size of the 2005 blueberry crop could be approximately 30 percent shorter than the 2004. Some early estimates indicate that this years’ crop will be around 52 million pounds with only 20 percent of the crop going into the fresh market. In 2004,
In the last two weeks the weather has been seasonable. Maximum daily temperatures have been in the 70s and the lows, generally in the 40s and 50s. The month of August ended with a few light showers five days apart. The more significant precipitation was recorded in the north. These first few days of September have been dry. Evapotranspiration is still relatively high. Soils are dry and would benefit from some rainfall.
Location |
GDD42 |
GDD45 |
GDD50 |
Hart |
3342 |
2911 |
2242 |
Ludington |
3196 |
2770 |
2111 |
Manistee |
3371 |
2947 |
2284 |
Cooler nights have brought the color to the apple fruit. It is becoming easier to spot a very nice crop load on the trees. Fruit size is surprisingly good considering the lack of rain through much of the season. Early varieties like Paula Reds, Ginger Golds and even some McIntosh are being harvested. McIntosh is showing signs of starch conversion moving it closer to the mature side of the scale. Though still testing immature, it is palatable and eating well. It has very good to excellent firmness. Some fruit drop is noticeable in certain blocks. That continues to be of concern. Application of Stop Drop is advised. Honeycrisp and Gala are moving along nicely. It appears that the Honeycrisp is maturing faster than Gala, which would be in line with our historical observations in a dry and hot season. Apple maturity testing has started a week ago.
Insects are very active. Our trap line is indicating that the codling moth numbers are dropping but are still well above the thresholds in most of the orchards. Scouts are reporting a noticeable jump in trap catches in several blocks indicating the beginning of third generation. This is not the time to “retire” the sprayers. Tight coverage for codling moth control is extremely important. Oriental fruit moth is another pest that requires attention. We are finding them in apple blocks in high numbers. OFM third generation flight peaked last week with more than 60 moths per trap. This week, there has been a significant drop, but the numbers are still high. There might be some issues with the OP resistance in much wider area than what we thought. There are increased numbers of Japanese beetles and yellow jackets in the orchards throughout the area. Apple maggot trap catches continue to be low. Obliquebanded leafroller larvae from the summer generation are expected to show up this week.
The disease situation seems to be under control for the most part. Some fire blight and powdery mildew symptoms are present in blocks scattered throughout the area.
Pears have been harvested. Moderate crop of pears, but very good size and quality.
Peach harvest is underway. Fruit size and quality is good. Very nice crop.
Greater and lesser peachtree borer numbers are declining but at the slow pace. Oriental fruit moth numbers declined significantly since last week when they peaked averaging at 61moths per trap.
Brown rot is of concern. Combination of protectants with other classes of materials is highly recommended to improve the efficacy of control. In combination, these materials are performing better than any one by themselves.
For the most part, there is a heavy load of plums on the trees. In few instances growers were reporting moderate to low crop load. Fruit has good size. Harvest is expected to start this week.
GDD 42 3488
GDD 50 2375
The northwest area received much needed rain at the end of August, but September has started out sunny and dry with cool nights. Temperature accumulations are still running ahead of the 15-year average
Apple harvest is underway here in the northwest. EarliGold harvest is in full swing, while Gingergolds and Paula Reds are now in the selective harvest phase. Apple quality is very good at this time. Codling moth trap catches are down from the past few weeks; the lowest counts we have seen all season. However, codling moth continues to be a pest for growers this year, especially as resistance may be playing an unexpected role in control. Obliquebanded leaf roller numbers are low in apple, while trap catches remain high in adjacent unsprayed cherry blocks. Oriental fruit moth trap catches are still high at this time. At the NWMHRS we have only captured one apple maggot fly thus far this season, which is unlike trap counts in other parts of the state.
In cherries, we are starting to see cherry leaf spot show up on new growth. Both sweet and tart cherries are showing symptoms, especially in blocks that did not receive a post-harvest fungicide application. Cherry fruit flies are still flying, but numbers are declining from prior weeks.
Peach harvest is underway, and pear harvest has also begun in the past week. Both fruits look exceptional in quality.
The area of high pressure that brought the sunny and dry Labor Day weekend weather was centered over
Temperatures behind the front will fall back to highs from the upper 60s north to upper 70s south and lows from the mid-40s north to upper 50s south by Thursday. Fair and dry weather with a gradual warming trend is expected later in the week with temperatures climbing back to above normal levels from near 80 north to the mid-80s south and lows from the mid-50s north to low 60s south by Saturday. The frontal system that passes through the state during the next couple of days is expected to return northward as a warm front by the early weekend, possibly leading to some showers or thundershowers by Saturday. Otherwise, more dry weather is expected through the end of the weekend into early next week.
In the medium-range time frame, the forecast guidance suggests a well-defined upper air troughing feature across western
The NOAA CPC 6-10 day and 8-14 day time outlooks, covering September 11-15 and the 13-19 are virtually identical. They call for above normal temperatures statewide and for precipitation totals ranging from near normal levels in southeastern sections of the state to above normal levels in the northwest.