Regional reports on Michigan fruit – July 24, 2012

MSU Extension educators’ pest and fruit updates for Michigan.

This week’s regional reports:

Southwest Michigan – Mark Longstroth, Bill Shane and Diane Brown, Michigan State University Extension

Southwest Michigan
Southwest Michigan

Weather

Last week was hot, with highs at 100 F at the beginning of the week. Temperatures then fell into the 80s as a cold front brought rain to the region on Wednesday evening (July 18) with a good soaking rain the next day (July 19). Rainfall amounts ranged from 0.7 to 1.5 inches. This rain recharged the topsoil and alleviated drought stress symptoms for most plants. Hotter temperatures returned by the weekend.

Weather for this week is forecast to be cooler with a chance of showers most days. Rainfall still lags behind evaporative demand, and all soils are drying out again. Our growing degree day accumulations continue two or more weeks ahead of normal.

Southwest Michigan Growing Degree Day Totals from January 1 through July 22

Location

GDD 42

GDD 45

GDD 50

Bainbridge

2816

2461

1916

Trevor Nichols

2703

2349

1807

Increase since 7/8/2012

258

227

183

Birds and raccoons continue to be a problem in fruit

Be sure and check the MSU Extension Fruit page at the new MSU Extension site for more information.

Small fruit

Japanese beetles have been spotty, but we can expect more to emerge after last week’s rain. Spotted winged Drosophila (SWD) trap numbers fluctuate up and down as temperatures rise into the upper 90s then go down into the 80s. We expect that SWD numbers will increase this coming week with cooler temperatures. We can expect a new generation every two to three weeks.

Strawberry growth is good where growers have irrigated. Potato leafhopper burn can be seen in some plantings. Day neutral strawberries in the high tunnels at the Southwest Michigan Research and Extension Center (SWMREC) are producing good quantities of reasonably sized berries despite the heat. Spotted wing Drosophila flies have been found in the tunnel strawberry plantings at SWMREC.

In brambles, blackberry harvest continues. We have seen sunscald on blackberries in field plantings. This disorder is caused by high temperatures and intense afternoon sunlight. Raspberry primocanes are over 3 feet tall. Growers should irrigate to maintain plant and fruit growth.

Blackberry sunscald
Blackberry sunscald.

Growers report spider mites, Japanese beetles and potato leafhoppers. Spider mites are the primary problem in high tunnel raspberries. Spotted wing Drosophila females were trapped in high tunnel blackberry and raspberry plantings at SWMREC. We are also seeing what we suspect is redberry mite damage on blackberries. This is characterized by uneven ripening of drupelets, with some turning black and others remaining red.

Redberry mite damage
Suspected redberry mite damage.

Blueberry harvest is moving rapidly in the heat. We are past the peak of the season. Fruit quality is generally good. Growers are machine-harvesting Jersey and other mid-season varieties. Harvest of late season varieties of Elliott and Liberty is underway. Birds are eating blue fruit in fields before they can be harvested.

Growers with irrigation have had a hard time maintaining adequate soil moisture during the hot, dry weather. Non-irrigated blueberry fields were so damaged by the hot, dry weather that most of the fruit have shriveled and in many cases the new growth has dried out. Spotted winged Drosophila numbers are expected to increase with cooler temperatures this week. Many growers are spraying for this pest as well as blueberry maggots. We can expect blueberry maggots to emerge following last week’s rain. See the Blueberry Insect Scouting Report July 15-21, 2012, for more information. Controls for anthracnose and Alternaria fruit rots should be maintained.

Grapes in established vineyards responded to the rain and berries are putting on size. Young vines were showing the effects of the heat and lack of soil moisture. Young grape vines lack the extensive deep root systems of mature vines. Juice grape bunches have closed. ‘Fredonia’ grapes are showing color, as are ’Mars’ and berries on ‘Marquette’ primaries. Wine grapes are at bunch closure. We expect to see the beginnings of veraison soon.

Japanese beetle feeding injury remains spotty. We reached 1,620 GDD base 47 in the southern part of Berrien County on Monday (July 23). This marks the beginning of third generation grape berry moth egglaying. The rest of the county and Van Buren County will reach this GDD accumulation sometime this week. Check the grape berry moth Enviro-weather model to check the progress of the model for your vineyard. Grape berry moth trap catches were light again last week. Rates of infestation for vineyards we scout ranged from one to four infested clusters per 50 cluster sample.

Grape disease pressure continues to be low. Recent, light rainfall may increase humidity, providing more favorable conditions for powdery mildew.

Tree fruit

Most tree fruit in the region continue to show drought stress. European chafer beetles, grasshoppers and Japanese beetles are chewing on leaves. Crawlers of the second generation of San Jose scale were expected to start emerging last week where the first generation was not controlled. Emergence should be at 300 to 350 DD50 after biofix, approximately Tuesday or Wednesday of this week (July 24-25). Flaring of European and two-spotted mites are common and in some cases can be traced to the use of pyrethroid insecticides types without miticidal properties.

Peaches are showing leaves with yellow stippling due to two-spotted spider mite feeding. Yellowing and drop of older leaves is common in sandy sites from a combination of stresses. Redhaven and PF11 Peach are being harvested with the varieties Starfire, Bellaire and John Boy coming up soon. Bird pecks are common on red fruit. The hot weather has caused some varieties to ripen on the outside of fruit earlier than the inside. Flavor of peaches continue to be generally very good.

Oriental fruit moth trap catches continue to be relatively light for the fourth week of the second generation. Infested fruit can be found in unsprayed orchards. Trunk sprays to control peach tree borers are usually applied in late June to early July, so we have reached the end of the traditional time to make these applications.

Cherry orchards are dry and cherry leaf spot is not a serious problem in either sweet or tart cherries. Post-harvest pruning of mature trees is probably not a good idea where trees are drought-stressed.

Plum tree decline is being seen due to a combination of drought stress and miscellaneous trunk problems. Leaf tattering and shot holes are common due to a wide variety of causes such as earlier frost damage, bacterial infection and physiological causes.

Apple fruits are generally 2.7 or more inches in diameter, with summer apple varieties such as Zestar at 3 inches. Red striping is starting to show on early coloring Red Delicious strains. Summer apple varieties, especially those with frost marks and cracks, are showing sunscald and miscellaneous rot symptoms on exposed sides of fruit.

Due to the early warm temperatures, predicted harvest dates for apples are up to three weeks ahead of normal. Pressure-testing and starch tests will be important to help determine when the apples are actually approaching maturity. The light apple crop will make harvest go quickly, but the hot weather will increase the tendency of fruit to drop quickly. NAA is generally applied as a stop-drop material when fruit start to drop, about two weeks or less before harvest, but not less than four days. The stop-drop chemical Retain is applied at least 28 days before harvest, but not earlier than 35 days.

Codling moth second generation flight has generally declined. Reports of obliquebanded leafroller feeding in foliage are generally uncommon. Oriental fruit moth second generation moth flight is continuing at a low level – fruit entries by the larvae can be found. Leaf bronzing from European red mites, two-spotted spider mites and rust mites is common. Apple maggot flies have been out for several weeks at relatively low numbers. Dry conditions can inhibit maggot emergence and we expect a spike in numbers when we get rain.

Pear fruit are about 2.5 inches or more in diameter on Harrow Sweet. Rolled leaves due to drought stress are being seen in orchards on sandy sites. Pear psylla is present in low numbers.

Meetings

The 23rd annual Viticulture Field Day will be held at SWMREC on July 25.

The final in-season grape meeting is scheduled for August 14 from 6 to 8:30 p.m. at Bob Dongvillo’s vineyard, 4930 Niles Rd., St. Joseph, Mich. (view map). The meeting cost is $15 and includes supper and 2 RUP credits. Please help us get keep meeting costs down by registering and paying in advance. The registration form should be mailed to Jamie at the Berrien County MSU Extension office, 1737 Hillandale Rd., Benton Harbor, MI 49022.

MSU’s Rufus Isaacs will be providing information about grape berry moth and other insects of interest as we get closer to harvest. MSU’s Annemiek Schilder will give an update on grape disease development, and MSU’s Eric Hanson will provide information about grape nutrition and foliar testing.

A hop production workshop will be held at SWMREC August 21 from 9 a.m. to 3 p.m.

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Southeast Michigan – Bob Tritten, Michigan State University Extension

 Southeast Michigan
Southeast Michigan

Weather

Drought concerns continue to deepen across southeast Michigan, despite some rain late last week. Signs of drought stress are becoming more evident in established tree and small fruits, with older leaves yellowing and dropping to the ground and even some wilting of leaves on the driest of sites. Drought stress has also resulted in reduced fruit size in blueberries and peaches, and collapse of fruiting terminals in fall red raspberries.

Rainfall late last week varied a great deal across the region, from 0.2 inches to 1.25 inches for farms just a few miles apart. These rain events brought only temporary relief from the drought. With the heat and windy conditions of this week, most if not all of that perception has now been lost.

Growers need to be checking newly planted fruit blocks every few days for signs of drought stress. Growers are devoting a great deal of time and energy to irrigation efforts.

Our early, warm season is still running more than two weeks ahead of normal in terms of growth stages, and with all of the heat of last two weeks we are back to being three weeks ahead of normal in terms of degree day totals.

East Michigan Growing Degree Day Totals for March 1 to July 23

Location

GDD42

GDD45

GDD50

Commerce (Oakland)

2689

2334

1789

Emmett (St Clair)

2653

2305

1769

Flint (Genesee)

2704

2347

1806

Lapeer (Lapeer)

2695

2344

1804

Petersburg (Monroe)

2835

2473

1915

Pigeon (Huron)

2531

2187

1664

Romeo (Macomb)

2740

2386

1837

Tree fruits

Apples are just over 2.5 inches in diameter where growers have a crop, with summer apples approaching 3 inches in diameter.

Apple maggot trap catch continues in high numbers, all on yellow sticky traps. With the rainfall of last week I saw a good amount in traps last week. I started to catch them on June 30 and high trap catches have continued since then. I find it interesting that growers are even finding high trap catches despite our soils being so dry.

Where apple growers have a crop this year, I continue to find that direct pests are seeking out fruit to feed on or breed in with a vengeance, resulting in far more fruit damage than growers are accustomed to finding. With this season’s heat and bright sunny days, insecticides tend to break down more quickly. Thus, growers with an apple crop need to tighten up their spray programs for apple maggots.

Potato leafhopper leaf curling continues to be very common in unsprayed blocks. I recommend that this pest be controlled in young apple blocks and in valuable varieties, like Honeycrisp. Codling moth trap catch has remained low and steady the last three weeks. Overall, we have had very high numbers of codling moths caught on traps from the first generation flight this season. Where growers have an apple crop this season, the second generation adult flight will need to be closely monitored and controlled.

Japanese beetles are being found in a few varieties, but their numbers have generally been lower this season than in the last few. European red mite and two-spotted spider mite populations are being kept in check by predators at most farms where there is no crop, however I am seeing some bronzing of leaves in a few trees where growers are controlling pests this season.

Powdery mildew-infected terminal branches continue to be prevalent and are dying back in unsprayed apple blocks. I am encouraging apple growers to keep a close eye on powdery mildew infections in valuable and susceptible varieties, even in blocks with no fruit. In unsprayed apple blocks, I am not seeing as much apple scab as I had expected to see; I attribute this to our dry season.

Pear psylla populations have finally leveled off in unsprayed blocks. Suckers need to be removed to help reduce pear psylla populations.

Peach harvest has begun on some early maturing Red Haven sites in the last few days on the few farms with a crop this season. Fruit size is being reduced from drought stress at most farms. I am getting a number of reports of raccoon, squirrel and bird damage to ripening fruit.

Sweet cherry and tart cherry leaf drop from cherry leaf spot disease continues, although the pace of leaf drop has slowed as most farms have applied a fungicide in the last few weeks. Japanese beetle leaf feeding continues at a few farms.

Plums look tough this season as a result of no crop at most farms and the lack of pest controls, and lately from drought stress.

Small fruits

Strawberry fields that have not had irrigation applied since renovation are looking tough over the last two weeks, mainly due to drought stress. Irrigation pipe needs to be reset and begin watering as soon as possible. Even where irrigation has been applied, fields are not rebounding as they typically do from the stress of renovation this season. Potato leafhopper leaf cupping and leaf margin burning is common in many new plantings. Where leafhopper controls have been applied in new berries this year, plantings look much better with a great deal of runnering taking place in the last week.

Raspberry harvest on fall bearing types from fruiting lateral canes or bud berries started in the last week at several farms. This harvest is rather limited. Harvest on summer-fruited types has wrapped up due to extensive cane collapse caused by a combination of dry soils and freeze damage. At these farms, harvest was less than 10 percent of normal years. Leaf drop of the lower leaves from drought stress is extensive in fall bearing varieties at most farms.

Spotted wing Drosophila trap catch started to be seen three weeks ago at farms that had trap catch last year. We are finding that trap catch declines a bit in hot weather, however it will increase again when cooler temperatures resume. Potato leafhopper feeding injury has caused extensive leaf cupping in many fall raspberry plantings over the last four weeks. Low numbers of Japanese beetles are being found, mostly in fall raspberry plantings.

Blueberry harvest continues, although small berry size from drought stress is starting to be a problem at many farms. Many varieties are being picked at the same time this season. There does not seem to be as much spread in ripening dates of varieties this year. Blueberry maggot trap catch is starting to be found at a few farms over the last week, especially where there has a good rain event. Japanese beetles are being found, mostly in low to moderate numbers. Remember to check spotted wing Drosophila traps. Bird feeding is extensive at most farms.

Grapeberry size is extremely variable this season due to freeze damage that killed most of the primary flower buds. Grape clusters are mostly at berry touch. Grape berry moth feeding injury is being found. Japanese beetles are being found, mostly in low to moderate numbers. Grapes have put on a great deal of new growth over the last few weeks.

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Grand Rapids Area Tree Fruit– Amy Irish Brown and Phil Schwallier, Michigan State University Extension

Grand Rapids Area
Grand Rapids Area

Crop update

The rain that fell last week has helped the Ridge and Hart/Ludington areas a lot in reducing water stress. However, keep a close eye on newly planted trees and the soil moisture levels there, applying supplemental moisture where needed.

For those with viable apples, we are in the window for Retain applications for several early varieties. Please refer to earlier articles at MSU Extension News on predicted apple harvest dates for more information. Retain is applied at its earliest about 30 days before anticipated harvest, but there are many ways you can use Retain to fit your own harvest plan. Gala harvest date is predicted for August 22, so we are right at that 30-day timing for Retain. McIntosh harvest date is expected to be August 27 and Honeycrisp, August 30, so Retain timing is near for those varieties as well. Keep in mind that these dates are nearly a full three weeks ahead of normal averages and later varieties are expected to be earlier than normal as well. Take a little time to sit down with your calendar and prepare how you might consider using Retain this year to manage your harvest.

Degree days are running ahead of normal averages by 21 to 24 days. A summary is provided in the table below.

Degree days (DD) through midnight, July 23, 2012

Weather station

DD base 32 from   Jan. 1

DD base 40 from   Jan. 1

DD base 42 from   Jan. 1

DD base 45 from   Jan. 1

DD base 50 from   Jan. 1

Rainfall   (inches) since Jan. 1

Belding

4,089

2,947

2,696

2,339

1,795

12.74

Clarksville

4,105

2,970

2,718

2,360

1,817

14.04

Fennville (TNRC)

4,233

3,032

2,769

2,398

1,842

12.72

Fremont

4,088

2,944

2,693

2,334

1,786

15.25

Hart

3,968

2,833

2,585

2,235

1,706

14.69

Hudsonville

4,322

3,131

2,868

2,495

1,929

9.90

Kent City

4,203

3,047

2,792

2,430

1,876

13.37

Ludington

3,843

2,715

2,472

2,126

1,609

15.51

Sparta

4,119

2,964

2,708

2,347

1,794

18.07

Average DD from Sparta historical data for Jan. 1 through midnight, July 23

3,285


2,045


1,286


Comparative Date of Averages at Sparta

Aug. 14


Aug. 16


Aug. 18


Days +/- Average

+22 days


+24 days


+26 days


Data from MSU’s Enviro-weather

Fire blight update

Fire blight continues to run in blocks that have it. Watch out for stormy conditions this week that rip or tear foliage and that will make it even worse. Until we get terminal bud set in apples, fire blight will continue to spread. I still see new active growth on many trees despite the dry conditions.

Brown rot in peaches

As we are nearing harvest of peaches, growers need to start considering tightening up their fungicide program to protect fruit from brown rot. The humid weather of late will enhance the spread of brown rot.

Tree fruit pests

Obliquebanded leafroller adult flight continues for the overwintering generation. Small larvae should be easy to find again soon.

Codling moth trap numbers of adult males have increased considerably in the last 10 days as second generation is now well underway. Since many are reporting trap numbers that did not get to zero, I am sticking with one biofix for 2012. If your blocks dropped to zero, you can set a new biofix to determine life stages and timings for cover sprays. With the warmer than normal temperature pattern we’ve been in, it probably doesn’t matter all that much. Codling moth does have an upper threshold of 90 degrees or so where it is not active, but remember, they fly at dusk so the temperatures at that time are not still in the 90s and they will be active as indicated by the trap numbers we are seeing in some orchards.

We have accumulated 1,471 DD50 since the May 3 biofix on the Ridge, indicating that second generation adult flight is underway and egg hatch is at about 35 percent. Many sites set a later biofix around May 18 – we have accumulated 1,351 DD50 since that date, which indicates that flight is underway and egg hatch is at 20 percent. This indicates that cover sprays are, again, important in blocks with viable fruit.

Looking ahead with forecasted temperatures, I expect we will reach peak egg hatch for the early biofix around the July 29 or 30. In blocks with a light crop, you will need to tighten up your codling moth management program rather than relax it – the percentage of damage could increase as the number of egglaying sites (fruits) is decreased.

Oriental fruit moth. A regional biofix was set for oriental fruit moth on April 15 and we’ve accumulated 1,967 DD45 since then. Flight of third generation is just beginning. We are in between generations of larvae now and cover sprays are not as crucial. Early egg hatch of third generation larvae is expected around August 1 or 2 and cover sprays will be needed again in stone fruits then. Be sure to closely watch preharvest intervals in peaches. In apple blocks with high oriental fruit moth trap numbers, this third generation can infest fruits, although this year it is likely to overlap with the end of codling moth egg hatch, so you will have cover sprays out there for both oriental fruit moth and codling moth.

Japanese beetles are present in normal numbers. There has been a slight increase in their activity in the last week, most likely due to the heavy rainfall a week ago that drives them out of their overwintering sites in the sod.

San Jose scale flight of the second generation of scale has started. Biofix for the second generation of San Jose scale was set for July 9 based on trap catches of adult males on the Ridge. We have accumulated 354 DD50 since July 9 and this indicates that San Jose scale crawlers should be completely emerged and the timing for management is right now. If the first generation was not controlled, the second generation is generally a worse problem and should be addressed.

Apple maggots have made an appearance for the 2012 growing season. I had reports of first trap catches on yellow boards late last week. If you are concerned about apple maggots, you need to get your traps up now.

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Grand Rapids Area Small Fruit– Carlos García-Salazar, Michigan State University Extension

Grand Rapids Area
Grand Rapids Area

Weather conditions during the last seven days have been dominated by hot temperatures reaching the upper 80s with some days reaching the mid-90s, so the conditions of intense heat and drought have remained. There were several thunderstorms in the area that left on average 0.5 inches of rain, but in general the high temperatures and drought are unchanged. For small fruit crops, prevailing weather conditions in the area continue to be stressful, but with some of the rains occurring during the past days there was some relief, especially for blueberry growers.

Currently, there still are some strawberries being harvested in counties north of Ottawa County with some day neutral fields still producing fruits of good quality. However, in most counties in Michigan’s central region strawberry growers have finished renovation and plant regrowth is underway. Growers need to maintain good irrigation to maintain healthy growth.

Regarding summer raspberries, the harvest has concluded with only small remnants in some fields. On the other hand, fall raspberries are in the bloom stage. At this time, supplementary irrigation is needed to maintain good growth, yield and fruit quality.

Current problems associated with raspberry production are spotted wing Drosophila (SWD) and Japanese beetles. In fields with some fruit leftovers from the summer harvest, SWD are reproducing and if uncontrolled, it will become a problem for fall raspberries. Thus, it is important that growers control this problem now to prevent further SWD infestations Growers need to be on alert and report to MSU Extension or pest consultants any suspicious fruit that may show decay symptoms with no apparent reason, especially if SWD were found in that field the previous season.

In blueberries, both mechanical and hand-harvest continues. Hand-harvest might be costly for fields where berries are small, so machine-harvest might be more advantageous. At this time, mid-season varieties and some Elliott fields are hand-harvested, and what remains of Bluecrop and other early season varieties are machine-harvested.

So far, the quality of blueberries continues to be good, but fruit size is smaller than during normal years. A partial reason for the fruit size problem is that the first bloom in most fields was damaged by late spring frosts and what is being harvested at this time are fruits from secondary flowers that normally produce fruits of inferior in size.

Insect and disease problems in general remain centered in SWD and Japanese beetles. When spraying insecticides against these insects, growers need to take in consideration the current weather conditions since most insecticides are affected by high temperatures and low relative humidity. For more information on this topic, read Counteracting adverse weather effects on deposition and degradation of insecticides used in berries.

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Northwest Michigan – Nikki Rothwell and Duke Elsner, Michigan State University Extension

Northwest Michigan
Northwest Michigan

Weather report

It has been hot and dry for the past two weeks. Daytime temperatures have been in the high 80s and the past two days (as of July 24) hit the low 90s; nighttime temperatures have stayed steady in the mid-60s. Conditions remain dry throughout the region and many growers are hoping for rain on the radar. A small amount of rain fell last week on July 19 at the Northwest Michigan Horticultural Research Center (NWMHRC) where we recorded 0.15 inches of rain. Thus far this season, we have accumulated 2,506 GDD base 42 and 1,659 GDD base 50. Soil moisture is extremely low at this time.

Crop report

All cherry harvest has finished now. Because of the small crop, growers have moved through the blocks very quickly and most growers were finished with cherry harvest within a week. The apple crop continues to look good and is sizing well. Growers that have a good apple crop have done an excellent job of managing the fruit. Red raspberry harvest continues this week. Drought stress is evident on trees without irrigation, particularly small trees.

Pest report

Cherries. Cherry leaf spot is still present in regional orchards and we continue to remind growers that we are still pretty early in terms of the growing season to discontinue cherry leaf spot applications. This dry weather has been helpful in minimizing the spread of cherry leaf spot. We are still recommending potentially multiple post-harvest sprays to keep leaves on until late August and into September. With the predicted rainfall and the high levels of inoculum in the orchards, growers should be covered up prior to this rain event to protect the foliage into the fall.

All insect levels are low this week, except for cherry fruit fly counts. As most growers are finished with harvest, the fruit that is remaining on the trees is vulnerable to cherry fruit fly infestation. The larvae that will develop in the fruit will contribute to a large cherry fruit fly population next season. Recent work has shown that a post-harvest cherry fruit fly application within seven days of harvest will reduce the cherry fruit fly population in subsequent years. As many growers did not harvest this year, there could be a larger amount of fruit left on trees that can be infested by cherry fruit flies. If growers are going out with a post-harvest cherry leaf spot spray, we recommend that growers add a lower priced neonicotinoid to the tank to help minimize next year’s cherry fruit fly population.

Again this week, spotted wing Drosophila (SWD) larvae have been observed in sweet and tart cherries left on the trees. We have been trapping for adults since mid-May, and during this last week, we have captured some adult flies in some isolated traps. Based on some of the infestation in fruit, we thought adult trap counts would be higher at this time.

Apples. We have observed little apple scab in area orchards here in the northwest. The dry conditions have been helpful in keeping this disease at bay. Growers should also note that strobilurin resistance has been confirmed in all major apple growing regions of the state and the mutation confers complete resistance – fungicides containing strobilurin will not work against apple scab and increasing the rate of a strobilurin is not an effective option.

Codling moth trap counts remain low at the NWMHRC this week. Growers that have a crop of apples need to be monitoring this pest diligently as they are internal feeders and will infest marketable fruit. With fewer apples in area orchards, codling moth will be competing to lay eggs in the reduced number of fruit that is available; therefore, growers need to be sure that fruit is covered at all times to minimize the risk of codling moth infestation.

Again, we emphasize that growers monitor for this pest in their own orchards as there is variability in the pest population from block to block; the degree day accumulation is HIGHLY dependent on the biofix date (the first date of sustained codling moth trap catch) for each apple block. Growers should track the progress on their farms using the Enviro-weather codling moth model and on-farm trap catch data.

Although we have been monitoring for this pest, obliquebanded leafroller summer generation larvae have been difficult to locate in regional orchards, but we remind growers that fruit should remain protected from larvae because these insects will feed on the fruit and result in unmarketable apples. There are materials that will control both codling moth and obliquebanded leafrollers in apples, and the use of these combination sprays will minimize costs for control of both of these pests.

Apple maggots have been trapped in low numbers at the NWMHRC.

Wine grapes. Continued warm and dry weather has been good for vineyards and berry development, even at sites without irrigation. Young vines without a well-developed root system may be getting into severe drought stress if they are not irrigated.

Potato leafhoppers are still fairly numerous, but not causing significant harm in most locations. Japanese beetles have remained at relatively low populations. Whiteflies have been found on some vinifera cultivars. This is a new situation for our area, so we have no indication of the significance of these pests in northwest vineyards.

The large sphinx moth caterpillars of summer are now appearing in northwest vineyards. There are three common species: the Pandora sphinx, the Achemon sphinx and the hog sphinx. The adults of these fly over an extended period, from as early as late May in some years all the way through to August. The larvae that hatched from eggs deposited by the earliest adults are now getting fairly large, in the 2- to 3-inch range. At this size, they can consume leaves at a rapid pace, completely defoliating a shoot in only a couple of days.

Pandora sphinx
Orange Pandora sphinx.

Pandora sphinx
Green Pandora sphinx.

Achemon sphinx
Achemon sphinx.

Hog sphinx
Hog sphinx.

It is very important to control these in first and second year plantings where they can significantly reduce vine growth. In older vineyards, their feeding injury does not typically have a significant impact on vine health or fruit quality, as the number of larvae is usually low and vines often have an excessive leaf canopy to begin with.

The Achemon and Pandora sphinx larvae have several different color phases in their populations, with a base color ranging from bright green through pink, rose, orange and shades of brown. Despite these various colors, they are still very difficult to find amongst the foliage of a grapevine.

There have been a few reports of powdery mildew in the area, but many vineyards still appear to be quite clean of this disease. This situation can change rapidly now that we have dense leaf canopies and susceptible clusters. If a bit of rainy weather and high humidity comes along, powdery mildew could become a more serious issue.

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