Southwest Michigan fruit update – July 9, 2024
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EmailMore hot, humid weather incoming.
Weather
Rain is expected this evening with much of southern Michigan in a flood watch. This rain is coming due to Hurricane Beryl, which landed in Texas earlier this week. The rest of the week is expected to be hot and humid with scattered thunderstorms in the later evenings. All of this rain and hot humid weather is expected to intensify disease pressure, so make sure to keep on top of your sprays. Additionally, the Michigan State University (MSU) Enviroweather legacy site will be down for the foreseeable future.
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Southwest Michigan growing degree-day (GDD) summary from March 1 – July 9, 2024 |
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|---|---|---|---|
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Station |
GDD 42 F |
GDD 45 F |
GDD 50 F |
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Benton Harbor (SWMREC) |
2199 |
1888 |
1417 |
|
Lawton (Lawton) |
2181 |
1872 |
1398 |
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Fennville (TNRC) |
2000 |
1699 |
1248 |
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Grand Junction |
2147 |
1842 |
1384 |
|
Average for the SW region |
2223 |
1895 |
1405 |
There is no weather report this week.
Tree fruit
Japanese beetle trap catch numbers have been significant for some locations over the past three weeks. Natural biological control for this insect generally kicks after three to five years of infestation. San Jose scale male trap catches at the Trevor Nichols Research Center in Fennville, Michigan, have been increasing over the past two weeks with the start of the second generation flight. Crawlers from this generation are expected 400-450 growing degree days (GDD) base 51 degrees Fahrenheit after the beginning of this flight, or in approximately two weeks with average temperatures. First generation crawlers typically emerge mid- to late June and second generation crawlers in mid-August. Warrior, Assail, Belay and Closer are nerve poisons that will have the best efficacy when targeting crawlers as they emerge. The insect growth regulators Esteem and Centaur also target crawlers but are somewhat slower acting because they disrupt insect development.
In peaches and nectarines, second generation oriental fruit moth trap catches continue to increase at the Trevor Nichols Research Center. Protection of fruit and new plantings against the second generation of oriental fruit moth is needed now. Leaf loss due to bacterial spot continues to be a concern on some sites. Peaches are harvesting about seven days earlier than normal. Recent rains have increased concerns about brown rot control.
In cherries, spotted wing drosophila larvae populations continue to build and are special concerns for late harvesting U-pick operations. Cherry fruit fly has also been trapped for the past three weeks at the Trevor Nichols Research Center. Brown rot and cherry leaf spot control continue to be the primary disease concerns, especially following recent rains. Post-harvest hedging of tart cherries helps to keep the interior of trees accessible to insect and disease management.
Apple harvest date predictions are available. The sooty blotch and flyspeck model on Enviroweather indicates conditions have been sufficient for these diseases to show up on apple fruit across the region. The fungal disease sooty blotch appears as green/dark sooty or cloudy blotches on waxy apple fruit. Flyspeck, also a fungal disease, looks like clusters of tiny black dots. Mancozeb, captan and Flint are commonly used to manage these diseases. Watch the preharvest interval for mancozeb, as indicated on the label. Protection against codling moth larvae and oriental fruit moth should be ongoing. Oriental fruit moth trap catches for the second generation are starting to increase. Apple maggot flies are a concern for sandy sites, especially following rains which promote fly emergence from soil.
Pears have the same concerns for codling moth and oriental fruit moth control now as apples. Obliquebanded leafroller is a sporadic pest which first targets leaves and then fruit. Sooty blotch and flyspeck are common problems on pears (see the apple section). Captan is not labeled for in-season use on pears.
Plum harvest of Early Magic, Kuban Comet and Early Golden Japanese plums are underway in some southwest area orchards. Brown rot and codling moth are the major management concerns.
Small fruit
Grape leaf pulling is underway. Tight-clustered varieties are at or near bunch closure.
According to the grape berry moth model (using May 19 as biofix and the Southwest Michigan Research and Extension Center as the site), the second generation should be laying eggs this week. You may have also heard reports of spotted lanternfly being found in Monroe County. See “Spotted Lanternfly Confirmed in Monroe County” from the Michigan Department of Agriculture and Rural Development for more information about their findings.
Significant powdery mildew and downy mildew infections are being reported in wine grapes. We are expecting 2 to 4 inches of rain tonight. With the established infections in the area and the humid weather connected with rain, be sure to have good fungicide coverage.
Blueberry harvest is underway in Van Buren County with early season varieties beginning to taper off. Disease focus should be on early fruit rot management. It has been excellent weather for anthracnose: Blueberry growers need to focus on Anthracnose fruit rot as bloom ends. Use systemic fungicides, which are absorbed into the plant, reducing fungicide wash off from sprinkler applications and rain events. This mild winter, early spring and the warm and wet summer have combined to make this a high spotted wing drosophila (SWD) pressure year. The numbers we see in traps are more like late August than early July, so intervals should be tighter. We should be looking to use the most effective chemistry possible. Here is an article about SWD in cherries. While a different crop than blueberries, many of the management basics apply.
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Strawberry harvest is done in Berrien and Van Buren counties. It is time to renovate perennial strawberry beds.
Upcoming meetings
The MSU Controlled Atmosphere (CA) Clinic on July 17 in Muskegon, Michigan, is organized by the MSU Department of Horticulture every other year to pass on new information relating to CA storage and warehousing of apple and other temperate fruit. This will be of primary interest to apple growers and storage operators.
The meeting this year features four internationally recognized leaders in apple postharvest science: Christopher Watkins (New York), Jennifer DeEll (Ontario), Carolina Torres (Washington State University) and David Rudell (U.S. Department of Agriculture Agricultural Research Service – Wenatchee) and Randy Beaudry (MSU). Sign up here.
The 2024 Michigan Viticulture Field Day is back for its 35th year. It will be held at the Southwest Michigan Research and Extension Center on July 31. Come for the education, stay for the steak dinner and local wine tasting. New this year, we are adding a second day for just the wine makers. The Michigan Enology Experience will be down the street from Southwest Michigan Research and Extension Center at the Lake Michigan College Welch Center the day after Viticulture Field Day on Aug. 1. We will talk wine production and tour some local wineries and see how they manage some of the challenges of winemaking in Michigan. Registration is available online.
Planning ahead for hot weather
The following information is from the MSU College of Human Medicine.
With a hot Michigan summer upon us, it is important to be mindful that hot weather can be dangerous while working outside. The heat produced by your body while working plus high outdoor temperatures makes it more likely for your body to overheat. To prevent overheating, do the following: drink plenty of fluids; take frequent breaks in the shade, and if possible, reschedule high energy tasks for earlier or later in the day.
Call 911 immediately if severe symptoms of overheating occur such as confusion, slurred speech, fainting, nausea/vomiting, rapid pulse, seizures, hot dry skin, or heavy sweating. Then, move the person to a cool place and help lower their temperature with a cool wet cloth and/or cool bath. Do not leave the person alone. Death can occur if the body does not cool down, so it is essential to have a plan before such symptoms occur.
This work is supported by the Crop Protection and Pest Management Program [grant no 2021-70006-35450] from the USDA National Institute of Food and Agriculture. Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture.
