sdsu extension newsletter july 13, 2012

South Dakota State University, South Dakota counties, and USDA cooperating. South Dakota State University adheres to AA/EEO guidelines in offering educational programs and services.

© 2012 Board of Regents, South Dakota State University

www.iGrow.org

News from our neck of the woods Scouting focus: spider mites in soybean and corn; soybean aphids; silk-‐feeding beetles in corn; potato leafhoppers in alfalfa

Dry weather in the Midwest has already brought spider mite woes to Indiana, Ohio, Iowa, and Nebraska, and we are getting reports of spider mites in South Dakota as well. Wet and humid weather promotes growth of pathogens that attack spider mites, so in wet years mites are unlikely to reach high numbers. Spider mites are not insects; they are arachnids and belong to a large family of mites (Tetranychidae) that earned their common name because many of them produce webbing when their populations are high. Spider mites feed on plants by piercing the plant tissue and sucking up contents of plant cells causing characteristic stippling damage (small spots). If their numbers are high, spider mites cause leaves to turn

yellow and drop from the plants. Spider mites can go through many generations each season, and in hot and dry conditions they can take as little as 10 days to complete development. There are several key predators of spider mites that keep their populations in check such as predatory mites, spider mite destroyers (small beetles from the same beetle family as ladybird beetles), and predatory thrips. Twospotted spider mites can be a problem in soybeans in dry summers, but there are no hard and fast economic thresholds for spider mites in soybeans. Spider mite treatment guidelines for soybeans are based more on observable plant damage than on counts, as the mites are hard to see. Spider mite damage usually starts in the lower canopy and progresses to the middle and upper canopy as populations build. A good rule of thumb is to treat when stippling reaches the middle canopy.

July 13, 2012

SDSU Extension Pest & Crop Newsletter

For the latest pest information, visit www.iGrow.org View newsletter online at www.iGrow.org/agronomy To sign up for the newsletter, email [email protected]

Entomology

Twospotted spider mites. Photo: Ada Szczepaniec

South Dakota Pest & Crop Newsletter July 13, 2012

2 © 2012 Board of Regents, South Dakota State University

Spider mite damage may resemble symptoms of drought stress or certain diseases so ensure that spider mites are present on the leaves before making decisions about pesticide treatments. Using a 10X hand lens is usually necessary to see the mites. A quick way to isolate them is to tap potentially infested foliage over black construction paper and examine the “grit” with your lens. Many pyrethroid insecticides can flare up spider mites further by repelling but not killing the mites, and eliminating their natural predators. Using an insecticide such as dimethoate may be a better option than pyrethroids.

Spider mites feed on the undersides of leaves and cause a stippling damage visible on the upper sides of leaves (left). Large infestations of spider mites cause the leaves to turn brown and drop from the plants (right). Photos: Galen Dively, University of Maryland

Twospotted spider mites and another spider mite species, Banks grass mites, can also be a significant pest in corn fields. Banks grass mites look similar to twospotted spider mites but the two dark areas run along the length of their sides, and do not end in the middle of their bodies. Research in Texas has demonstrated that both species of spider mites have similar potential to damage corn so the same thresholds should be used in decision-‐making process for both twospotted and Banks grass mites. Both species of spider mites reproduce fast, have multiple generations per season, and their generations times are very short. Spider mites can complete their development in as little as 10 days in dry and hot conditions. To scout for spider mites, inspect at least 10 plants throughout the field. Make note of the

proportion of green corn leaves that are infested with spider mites on each plant, and record the percentage of leaf area on each infested leaf that is damaged by spider mites. Symptoms of spider mite damage to leaves include chlorotic (white to yellow) spots on plant tissue where spider mites sucked out the contents of plant cells. We tend to overestimate percent damage usually, so be conservative in estimates of percent area that is damaged. Use the table below to evaluate if pesticide applications are recommended based the cost of

Twospotted spider mite (left) and Banks grass mite (right). Banks grass mites have dark green areas that run along the length of their bodies. Image: University of Nebraska, Lincoln, Extension.

Spider mite damage to corn. Photo: A. Szczepaniec



treatment given the market value of the crop. Alternatively, use guidelines established by the extension specialists in Colorado, who recommend treating if damage is visible in the lower third of the plant, and spider mite colonies are visible in the middle third of the plant. Because eggs of spider mites are not killed by pesticide applications, scouting for spider mites should be repeated after treatments. Before the initial pesticide applications, clearly mark 25 leaves infested with spider mites throughout the field, and inspect those leaves after pesticides have been applied and the field re-‐entry period has passed. If there are mobile stages of mites present on those marked leaves approximately 5-‐7 days after the initial treatments, additional applications may be necessary. It is important to note that according to research done in Texas and Colorado, corn yield is unlikely to benefit from pesticide applications to manage spider mites after the dent stage. Again, once corn is in the hard-‐dough stage, there is no benefit from treating for spider mites. Adhering to thresholds is important because there are many natural predators of spiders mites that are effective at keeping their populations in check. Applying pesticides before it is necessary will annihilate natural predators and further exacerbate potential for spider mite outbreaks. At the end of this newsletter, we are providing a table with pesticides registered for spider mite control in corn and soybeans. (A.S., B.H., and K.T.)

Economic injury level for the spider mites attacking corn. Pesticide applications should be considered when economic injury levels are reached. Source: Texas A&M University, Extension Publication E-‐400. This table is for corn values at or lower than $700 per acre, and Bob Wright, University of Nebraska Extension specialist provided the following for market values that exceed $700 per acre: Use the following formulas to determine an economic injury level. 1. For percent infested leaves the formula is (cost of control x 600) ÷ (price per bushel x bushel yield). 2. For percent of leaf area damaged the formula is (cost of control x 312) ÷ (price per bushel x bushel yield).



Corn rootworm adults are emerging and moving to above-‐ground plant tissues to feed. It is important to scout for them now to assess their potential for damage to corn plants this year, and because their presence will be a good indicator if corn rootworm larvae are likely to be present in those fields next year.

Western and northern corn rootworms, the two species of corn rootworm that cause severe economic damage to corn in the Midwest, have one generation per year. Adult corn rootworms emerge in late June and early July, and begin to lay eggs in mid-‐summer and continue until fall. Adults of western and northern corn rootworm can consume corn silks, and if their populations are high, their damage to corn silks can interfere with pollination and result in corn ears that are poorly filled. Western corn rootworm adults also feed on green plant tissues,

and in very high numbers they can strip a layer of leaf tissue leaving only a thin, dry, and almost see-‐through layer behind. This type of damage is severe, and indicates presence of a very high population of western corn rootworms. Because adults are mobile, it is important to make note of them not just in corn fields, but adjacent fields and field margins as well. They can be seen mating and feeding on plants. Their presence indicates potential for larval activity the following year. To predict if the adults will affect plants this year, scout for adults shortly before and during corn silking. Scouting should take place in the morning and late afternoon, when the beetles are most active. It should continue every 2-‐3 days until silks turn brown. To assess if adult feeding will affect

pollination of this year’s crop, walk through the field and look for beetles on corn ears. Inspect silks on plants in those fields where you see 3-‐5 beetles per corn plant. In addition to adult corn rootworms, Japanese beetles may also be present in the ear zone area of corn plants, and may cause silk clipping, so take a note of both kinds of beetles. Inspect at least five plants in five different areas of the field. If silks are still green, measure their lengths: ½ inch of silk is sufficient for pollination so even if there are beetles present on plants it is not necessary to manage adult corn rootworms if silks are longer than ½ inch. If silks are already brown, no control is necessary. Silks clipped to less than ½ inch in length and still green warrant chemical control (e.g. dimethoate, bifenthrin). I would caution against using pyrethroid insecticides other than bifenthrin since they are known to flare up spider mites, which are also associated with dry and hot conditions.

Northern corn rootworm. Photo: Marlin E. Rice

Western corn rootworm. Photo: Ada Szczepaniec

Leaf striping by adult western corn rootworm. Photo: A. Szczepaniec



White grubs in pastures. Photo Credit: www.ag.utah.gov

Because applications of pesticides during pollination will harm pollinators, it is very important to adhere to these management recommendations. Healthy communities of pollinators are necessary for agricultural production, and it is critical to minimize the impact of any potentially negative management practices to pollinators. (A.S.) Many thanks to all who called with information about adults of corn rootworms in corn fields. If you have seen these insects in your area, or suspect corn rootworm larvae in a Bt field, please give me a call (605-‐688-‐6854) or send me an email ([email protected]). Source: Purdue University, Extension publication E-‐49-‐W

More reports of grub damage are coming in from around the state of white grub damage in pastures. We had dealt with this problem earlier in the year, but because the category “white grubs” contains so many different species, there are a number of different lifecycles that are taking place simultaneously. Some species of white grub can take about 1 year to develop into their adult stage while others, however, can

take up to 3 years before emerging as an adult. If your pastures are being injured by grubs, it is recommended that samples be sent in for proper identification. In this case physical samples are preferred over pictures because it is necessary to view their tail end under a microscope and examine the pattern of hairs present to identify the species. Unfortunately, there are no chemical treatments or preventatives available for use in pastures because of the risk to grazing livestock. Heavy watering and biological control are the only management options available to landowners. However, when dealing with these grubs, the best offense is most definitely a good defense (preventative measures). Maintaining healthy pastures, plowing fields, and preserving natural enemy populations are all recommended methods to preventing future grub issues. If the sod is

dead or if it has gotten torn up by opossums, raccoons, or badgers feeding on these grubs, it might be best just to till it up and reseed in the fall if possible. (JN)

Japanese beetles have metallic brown hind wings and metallic green thorax. They have white tuffs of hair along the sides of their bodies. They can clip corn silks as well if they are present in corn fields. This is not usual but certainly possible, especially if their populations are high. High numbers of these beetles have been noted on corn plants in Iowa this year. Photo: Ada Szczepaniec



Updates from our neighbors

Spider mites are a problem about everywhere around us owing to hot and dry conditions. Wheat stem sawflies have caused some yield loss in wheat in western Nebraska. Banded sunflower moth is in North Dakota, and I have found many of them in South Dakota as well, near Watertown. More on this and other sunflower pests here: www.ag.ndsu.edu/pubs/plantsci/pests/e1457.pdf (A.S.)

Predator of the week: Tiger beetle As I was walking out of my building one evening this week, I spotted many tiger beetles flying around on the sidewalk. These beetles belong to a large family of predatory beetles, Carabidae. There are many species of tiger beetles in the U.S. and the one I was lucky to capture on a photo this week is the backroad tiger beetle (Cicindela punctulata). Despite their common name, they are common on city sidewalks and not just back roads! Most tiger beetles have the same characteristic body shape, and differ in the color and markings on the elytra, which are the hardened hind wings of all beetles. They are exquisite hunters. They can be spotted on sunny days, and have a very characteristic short-‐flight pattern. Tiger beetles have great eyesight, which contributes to their skillful predatory habits, but makes them tough to catch to take a closer look. Both adult and immature tiger beetles are predators, and they hunt anything they can get their mandibles on. Here is a link to a fun article about them written by my former adviser at the University of Maryland, Mike Raupp: http://www.bugoftheweek.com/BugOfWeek_16Ga.html. Mike recorded another species of tiger beetles, the six-‐spotted tiger beetles common in the east, so you can take a closer look at these

very cool predators. (A.S.)

Banded sunflower moth. Photo: A. Szczepaniec

Backroad tiger beetle happily hunting the days away. Photo:



Consider delaying Canada thistle control during dry conditions It is difficult to know exactly how the current drought conditions may affect herbicide efficacy on Canada thistle, but it may be best to wait rather than try to control Canada thistle in drought stressed pastures. SDSU field research over the past 4 years has demonstrated that herbicides like Milestone (aminopyralid), ForeFront (aminopyralid + 2,4-‐D), and Tordon (picloram) may be effective if applied any time between mid-‐June and early October. A long time duration for herbicide applications means we have the luxury to wait for good growing conditions. Actively growing plants will translocate the herbicide to the roots more readily. If you do decide to make herbicide applications in pastures now, it may be helpful to include a surfactant to increase herbicide movement into the weed leaf. During dry conditions, the waxy cuticle on the leaf surface may become more dense making it difficult for fluids to move into the leaf.

Herbicide restrictions for harvesting corn as forage As the drought becomes more severe and it becomes clear that corn is not going to produce grain, people may consider chopping the corn for forage (see the UW Extension page http://wisccorn.blogspot.com for info on evaluating the potential for harvesting corn forage). However, there may be forage harvesting restrictions associated with the herbicides that were applied earlier in the season. Many herbicides have a restriction of about 30 – 60 days between application and harvest. Since many herbicides were likely applied in early May, it could be permissible to harvest corn forage now. However, harvest restrictions should be verified for each herbicide used. Some common herbicides and their associated harvest restrictions include:

Weeds



Corn Forage and Grazing Restrictions (days after application) Herbicide Forage Grazing

Roundup (glyphosate) 50 50 Liberty (glufosinate) 60 60 Callisto (mesotrione) 45 45 Laudis (tembotrione) 45 45 Impact (topramezone) 45 45 Cadet (fluthiacet) 30 30 Resource (flumiclorac) 28 28 Starane (fluroxypyr) 7 7 Status (dicamba + diflufenzopyr) 32 -‐-‐

It’s soybean cupping season As pasture herbicide applications progress, we may see some soybean leaf injury due to 2,4-‐D drift or vapor movement. Soybean plants become more tolerant to growth regulator herbicides as they get older, so minor leaf damage may not cause any soybean yield loss. Under normal conditions, soybean plants generally grow out of the injury symptoms quickly. However, recovery may be slower during dry conditions. SDSU research has indicated the relationship between soybean leaf injury and yield loss is highly variable among years and locations. Therefore, monitoring yields at harvest is the only reliable method of quantifying soybean yield loss. In many cases, people may wonder if the growth regulator herbicide came from the air (e.g. drift, vapor, tank contamination) or the soil (e.g. carryover). We can speculate that the herbicide came from the air if only the top leaves are deformed. Carryover injury will often cause injury on all the leaves and may cause skips in the soybean rows. Additional pictures and information may be found at mikesweeds.com.(MM)

Upper leaves are most injured when herbicide exposure comes from the air.



Carryover injury from growth regulator herbicides causes injury on all the leaves, severe stunting, and skips in the soybean row.

Soil sampling after small grain harvest: The small grain harvest is underway in earnest with 41% of the winter wheat and 20% of the oats harvested as of July 8th. The harvest is two to three weeks earlier than normal. Is it too early to soil sample these fields? Most soil nutrients, pH and other tests are fairly stable throughout the year. The exceptions are nitrogen, sulfur and to some degree – potassium. Available soil nitrogen (mainly in nitrate-‐N form) will vary throughout the season depending on plant growth, soils, leaching, fertilization, immobilization and mineralization of organic material. Usually after harvesting a good crop, soil nitrate-‐N is very low because of plant uptake. Long term summaries of South Dakota soil test data show these levels slowly increase into late fall. The amount of increase varies yearly due to factors such as tillage, residue, temperatures and precipitation. If winter wheat is to be grown, it is advisable to obtain a soil sample at least 2-‐3 weeks before seeding to allow time to make seeding time nutrient additions. Although nitrogen is usually applied for winter wheat in late fall or early spring, the nitrate-‐N test has been calibrated for this crop with August and September soil samples. Therefore, even though there may be more available soil nitrogen in November than in August, that difference is taken into account. For planting of spring seeded crops, it is usually advisable to wait until after mid September to begin sampling. However, if possible weather, laboratory or other delays are anticipated, get it done when expedient. Plant available sulfur levels can also increase with organic matter mineralization but the change is relatively small. For both sulfur and nitrogen it is important to obtain a sample to the 2 foot depth (0-‐6 and 6-‐24 inch depths) to obtain the carryover levels of these mobile nutrients.

Soils



Soil test potassium can vary from season to season depending on soils, soil moisture and crop growth. It is not unusual to see 50 ppm differences in K soil tests from one year to the next when levels are in the 150 to 200 ppm range. Higher variability is often seen with higher soil test levels. With good small grain yields expected in many areas of the state – we would anticipate lower than average nitrate-‐N levels in the 0-‐2 foot sample depth. In addition, possible nitrogen volatilization losses from early spring urea applications this year may also lead to lower N levels in some fields. However, there are also stressed fields where yields will not exceed yield expectations or fields with heavy N applications that may have significant nitrate-‐N carryover. All these variables and more make it necessary to sample each field each year. Even for tests such as P, K, pH and zinc which are relatively stable, every year sampling gives a good baseline to compare your most recent analysis. Any extreme variability from this baseline can then be examined, regardless of the cause. (RG) Common bunt, also known as stinking smut, becomes readily apparent during wheat harvest, as the fungal structures called “bunt balls” resemble wheat kernels. As a combine moves into affected fields, the bunt balls, which are completely filled with black teliospores often erupt into a black cloud. Common bunt reduces both grain quality and yield. Grain contaminated with common bunt has a darkened appearance and a fishy smell. If detected, contaminated grain is often discounted at the elevator, and can be rejected. It is unusable as feed because the strong odor will cause the livestock to reject it. Common bunt can be soil and/or seed borne, requiring aggressive management. Recommended practices include crop rotation, planting certified, disease-‐free seed, and systemic fungicide seed treatment. Common bunt spores have been known to survive for several years in soil. Protectant fungicide seed treatments can work, but if planting into a field with a history of common bunt, seedlings which emerge in soil which contains common bunt spores, and/or delayed germination due to dry conditions can still result in infection. The high rate of systemic seed treatments will extend the time of protection and protect seedlings growing into zones of soil containing spores. For more information, access: ExEx 8005, “Recognizing and Managing Common Crop Diseases in South Dakota”: http://pubstorage.sdstate.edu/AgBio_Publications/articles/ExEx8005.pdf, “Diagnosing Wheat Production Problems in Kansas”: http://www.ksre.ksu.edu/library/crpsl2/s84.pdf, ”Managing Crop Diseases with Seed Treatments”: http://igrow.org/up/resources/03-‐3001-‐2012.pdf, and “Seed Treatment Fungicide Options for Wheat in South Dakota”: http://pubstorage.sdstate.edu/AgBio_Publications/articles/FS965.pdf. (B.F.)

Crop conditions continued to worsen in South Dakota this past week as received little or no rain, with high temperatures, and wind. This caused additional stress on crops in the region. Crop prices have also been increasing with the cornbelt also affected by drought. So as yields projections have been reduced,

Diseases

Crops



prices have made up for some of that shortfall in revenue. Drought conditions seem to be the topic of discussions across the state with the Drought Monitor released last week showing most of South Dakota either abnormally dry, moderate drought or severe drought. The new report is issued weekly at the USDA Drought Monitor for the US and for each state. The Crop Progress and Condition Index was released July 8th and showed a major change the last two weeks to crop conditions. The corn crop condition index lost 17 points from a week ago. The good/excellent category lost 6 points this past week from the week prior in SD. Much of corn crop has lost yield potential with the continued dry conditions. Twenty four percent of the corn crop is silking as of July 8th. The Soybean crop condition lost 13 points from a week ago. The good/excellent category lost 4 points from a week ago in SD. With forty five percent of the Soybeans blooming now, hot and dry conditions can start to affect yield. Winter Wheat conditions improved 6 points this week after losing 13 last week but harvest is progressing in SD. Forty one percent of the winter wheat has been harvested as of Sunday, July 8th. Spring Wheat conditions declined 3 points this week after losing 25 points last week in SD. (DG) July Climate Outlook (from the previous issue but still relevant) The latest monthly outlook for July 2012 was released last week. A high probability of above average temperatures covers most of the lower 48 states, including all of South Dakota. For precipitation, the state has equal chances of above, below and near normal precipitation for July. This is more optimistic than the previous outlook, which had higher probability of below normal precipitation in the southeastern part of the state. The heart of the Corn Belt appears to have the worst outlook at this time, with above normal temperatures and below normal precipitation projected for the next month, during a crucial time for corn development in particular. (L.E.)

Weather



Above: July 2012 temperature outlook. Orange colors depict higher probability of above normal temperature for the month.



Above: July 2012 precipitation outlook. Brown colors indicate higher probability of below normal precipitation for the month. Green colors indicate higher probability of above normal precipitation for the month. (Graphics courtesy of NOAA Climate Prediction Center, http://www.cpc.ncep.noaa.gov/products/predictions/30day/)



South Dakota State University IPM Field School for Agronomy Professionals

July 26 and 27, 2012 Southeast Research Farm Beresford, South Dakota

The Integrated Pest Management (IPM) Field School provides the latest, most up-‐to date information. Presentations include hands-‐on-‐activities or field demonstrations in small groups to encourage interaction between presenter and participants. A total of 10.5 CCA continuing education credits will be awarded for the two day school. Thursday and Friday noon lunches, break refreshments, and Thursday evening supper will be provided. The 2012 IPM Field School session topics are:

• Weed Management: Crop Injury Characteristics and Weed Identification • Soybean Cyst Nematode and Corn Nematodes • Scouting and Identifying Common Soybean Diseases and New Diseases in Corn • Precision Agronomy: Variable Rate Fertilizer Application • Know Thy Enemy (And Thy Friend): Scouting, Identification and Thresholds for

Major Insect Pests of Corn, Soybeans, and Forage Crops • Soil Salinity and Why We Are Seeing the Problem • Climate Trends Impacting Agriculture

Directions to the Southeast Research Farm from Beresford, SD: Travel 5.5 miles west of Beresford on SD Hwy 46, turn south on University Road and drive 3 miles. The Research Farm is on the east side of the road. For more information contact: Darrell Deneke, SDSU Extension IPM Coordinator 605-‐688-‐4595 Email: [email protected] Registration information is available from the South Dakota Agri-‐Business Association at: Phone: 1-‐800-‐994-‐2445 or 605-‐224-‐2445. Online: http://www.sdaba.org The IPM Field School is sponsored by: South Dakota State University Extension IPM Program South Dakota State University, Plant Science Department South Dakota Agri-‐Business Association

Events



This event is organized by our colleagues at University of Minnesota:

Farm Groups to Host Nitrate Education Event

Nitrogen is a common element and one of the basic building blocks of protein. But concerns arise when nitrates, one form of nitrogen, are found in elevated levels in wells, lakes or streams. Several state agencies conduct nitrate monitoring programs across Minnesota, primarily focused on drinking water. Agricultural researchers are exploring the connections between fertilizer use and water quality, while also looking for production practices that minimize the potential for nitrate contamination.

The Minnesota Agricultural Water Resources Center (MAWRC) will host a free seminar “Minnesota Agriculture and Nitrates”, to highlight some of the most recent monitoring data and research If you have ever wanted to learn more about nitrates and how it affects plants, animals, people, water and land, be sure to attend.

According to event co-‐organizer Dr. George Rehm the line-‐up of speakers will include experts in several different aspects of nitrates, from Minnesota water monitoring programs to efforts to reduce nitrate runoff to the Chesapeake Bay. “We want to simply provide a forum that brings farmers, ag professionals and agency staff together to talk about what is known relative to nitrates in Minnesota. We want to get past perceptions and focus on science,” said Rehm, a recently retired University of Minnesota Extension soil fertility specialist and MAWRC Discovery Farms Coordinator.

This educational event is made possible by the financial support of the Minnesota farm organizations comprising the MAWRC, a research and education organization dedicated to the protection of water quality and the continued advancement of agriculture in Minnesota. The seminar will be held at the Rochester International Event Center, from 9:30 a.m. to 3 p.m. on Wednesday, July 25, 2012.

The Center is located at 7333 Airport View Drive Southwest, Rochester, Minn. just off of Highway 63 and near the Rochester International Airport.

The Minnesota Agriculture and Nitrates seminar includes a free noon meal, and pre-‐registration is not required. For more information and to view the full agenda go to www.mawrc.org.

Other upcoming events:

July 28: Organic Field Tour, SE Research Station



Contributing Authors

Ruth Beck, SDSU Agronomy Field Specialist Darrel Deneke, SDSU IMP Coordinator Laura Edwards, SDSU Climate Field Specialist Bob Fanning, SDSU Plant Pathology Field Specialist Ron Gelderman, SDSU Extension Soils Specialist Don Guthmiller, SDSU Extension Agronomy Business Management Field Specialist Buying Hadi, SDSU Pesticide Education and Urban Entomology Coordinator Mike Moechnig, SDSU Weed Specialist Jonathan Nixon, SDSU Entomology Field Specialist Ada Szczepaniec, SDSU Extension Entomologist, Editor Connie Tande, SDSU Microbiologist, Plant Clinic Kelley Tilmon, SDSU Soybean Entomologist Larry Wagner, SDSU Agronomy Field Specialist



Examples of Insecticides labeled for mites control on corn in South Dakota* Active Ingredients (Insecticide class)

and Examples

Pests Rate Re-entry

interval

Notes and restrictions

Bifenthrin (Pyrethroid)

Brigade 2EC Banks grass mite Two-spotted spider mite

5.12-6.4 fl oz/A

12 hours • Do not apply within 30 days of harvest.

• Do not graze livestock in treated areas or cut treated crops for feed within 30 days of the last application.

• Do not make aerial or ground applications to corn if heavy rainfall is imminent.

Tundra EC Banks grass mite Two-spotted spider mite

5.12-6.4 fl oz/A

12 hours • Do not graze livestock in treated areas or cut treated crops for feed within 30 days of the last application.

• Do not apply within 30 days of harvest.


Discipline 2EC Banks grass mite Two-spotted spider mite

5.12-6.4 fl oz/A

12 hours

Zeta-Cypermethrin & Bifenthrin (Pyrethroids)

Hero Banks grass mite Two-spotted spider mite

10.3 oz/A

12 hours • Do not apply within 30 days of harvest for grain and stover and 60 days for forage.

• Do not graze livestock in treated areas or cut treated crops for feed within 30 days of the last application.




Dimethoate (Organophosphate) Dimate 4E Banks grass

mites Two-spotted spider mites

2/3 – 1 pt/A

48 hours • Do not feed or graze within 14 days of last application.

* This list is not meant to be comprehensive. The information may change and is not meant to supersede the label. Users MUST read and follow the direction of usage on the label of each insecticide. Examples of Insecticides labeled for mites control on soybean in South Dakota*

Active Ingredients (Insecticide class)

and Examples

Pests Rate Re-entry

interval

Notes and Restrictions

Bifenthrin (Pyrethroid)

Brigade 2EC Two-spotted spider mite

5.12 to 6.4 fl oz/A

12 hours • Minimum interval between applications: 30 days.

• Do not apply within 18 days of harvest

Tundra EC Two-spotted spider mite

5.12-6.4 fl oz/A


• Do not apply within 18 days of harvest.

Zeta-Cypermethrin & Bifenthrin (Pyrethroids)

Hero Two-spotted spider mite

10.3 oz/A


• Do not graze or harvest treated soybean forage, straw, or hay for livestock feed.



Chlorpyrifos (Organophosphate) Lorsban 4E Spider mites 0.5 – 1

pt/A 24 hours • When large numbers of eggs

are present, scout the treated area in 3 to 5 days. If newly hatched nymphs are present, make a follow-‐up application of a non-‐chlorpyrifos product that is effective against mites.

• Pre-‐harvest Interval: 28 days. • Do not make a second application of Lorsban 4E or other product containing chlorpyrifos within 14 days of the first application.

• Do not allow meat or dairy animals to graze in treated areas or otherwise feed treated soybean forage, hay and straw to meat or dairy animals.

Nufos 4E Spider mites 0.5 – 1 pt/A

24 hours • When large numbers of eggs are present, scout the treated area in 3 to 5 days. If newly hatched nymphs are present, make a follow-‐up application of a non-‐chlorpyrifos product that is effective against mites.

• Pre-‐harvest Interval: 28 days. • Do not make a second application of Nufos 4E or other product containing chlorpyrifos within 14 days of the first application.

• Do not allow meat or dairy animals to graze in treated areas or otherwise feed treated soybean forage, hay and straw to meat or dairy animals.

Dimethoate (Organophosphate)

Dimate 4E Spider mites 1 pt/A 48 hours • Do not feed or graze within 5 days of last application.

• Minimum interval between applications: 7 days.

* This list is not meant to be comprehensive. The information may change and is not meant to supersede the label. Users MUST read and follow the direction of usage on the label of each insecticide.

sdsu extension newsletter july 13, 2012

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