With temperatures reaching into the 90s midweek and rainless storms bringing winds of 35-65 mph, tillage and recently tilled fields contributed to large and small dust storms developing across the state. (Photo by Brett Hampton)

May 7, 2004

State splits over soil moisture; drought declared

Drought area grows Much of western and southwest Nebraska is now in a severe or extreme drought. With some areas of the state facing their fifth year of drought, Nebraska Gov. Mike Johanns Monday declared the state to be in a drought emergency. (See May 7 AgNews.)

If normal temperatures are recorded during the corn production season, the crop should reach maturity a full 10-14 days ahead of schedule. Reproduction could begin as early as the first week of July. If temperatures remain above normal during the next 30-45 days, pollination and crop maturity could be moved ahead another 7-10 days.

Soil moisture conditions across Nebraska are at both ends of the spectrum. In east central and southeast Nebraska, field surveys indicate full soil profiles down to four feet, with most fields having moisture down to 5 feet. This is a significant improvement over the last few springs when producers were counting on May rains to make up for significant deficits incurred during the fall-spring period. Northeast Nebraska has fairly adequate moisture with five to six inches of estimated moisture in the top five feet of profile. If May precipitation is normal, full soil profiles can be expected by June 1.

The real soil moisture problems continue to occur throughout western and southwest Nebraska, where some areas are facing their fifth straight year of drought. The U.S. drought monitor currently rates much of the Panhandle and southwest Nebraska as being in an “extreme drought” while another large area of northwest and north central Nebraska is described as being in a “severe drought.”

There was significant precipitation April 19-25 with almost all locations reporting at least one inch of moisture and many reporting more than two inches. This moisture may provide some short-term relief for the wheat crop and enhance planting; however, rainfall will need to remain timely and generous throughout the remainder of the growing season to aid moisture-starved soil profiles. Almost all locations across western Nebraska have less than four inches of available moisture in the soil profile, with most having less than two inches.

There has been an unusual swing in extreme temperatures during the last 30 days across the state. Temperatures have pushed into the low 90s, while lows have flirted with the upper teens. It doesn’t appear that freezing temperatures are in the forecast during the next 10 days, but above-normal highs can be expected. Temperatures are expected to move into the 80s and possibly low 90s next week.

For more information . . . on the drought and recommended farming practices to mitigate its effects, check the CropWatch archives and these sites: UNL Drought Web site at http://ianrhome.unl.edu/drought/ National Drought Mitigation Center at http://www.drought.unl.edu/ Drought Central, Nebraska Department of Agriculture Web site, at /http://www.droughtcentral.org/ Nebraska Climate Assessment and Response Committee at http://carcunl.dnr.state.ne.us/docs/press.html

The large ridge across the western United States has played a key role in these warm conditions. Snowpack levels continue to rapidly deteriorate and could be virtually non-existent by late May. As of now, the ridge has shown the ability to move eastward and flatten out. As the Pacific Northwest trough moves eastward, it is rapidly replaced by the strong ridging pattern.

This trough-ridge pattern is giving the state a shot at significant moisture for a 2-4 day period, followed by 10-14 days of dryness. If this pattern continues through the summer, good yields can be expected and it will aid western irrigators. However, based on the strength of the western ridge this early in the year, conditions are looking eerily similar to 2002 across the western third of the continental United States. Our concern is that the ridge may become permanently established by early June, leading to significantly drier weather and above normal temperatures this summer. May will go a long way in determining how vulnerable the state will be to expanding drought conditions as the summer progresses.

Wheat too escapes significant damage Although there was some leaf tip burning in wheat as a result of the cold weather last week, the Panhandle wheat crop was not at a particularly susceptible stage for damage. Moisture that preceded the cold snap also lessened the potential negative effects of the freeze. Some small isolated areas may see damage such as stem breakage later in the year as grain begins to develop in the head, but little other damage is expected. Over the next couple of weeks, wheat will begin to head and flower and then subfreezing temperatures would be much more devastating to yield. Drew Lyon Extension Dryland Cropping Specialist

Lows on Sunday morning dipped to 19^oF at Alliance and 20^oF at Chadron, according to National Weather Service data. Columbus had a low of 27^oF on Monday morning.

While these temperatures are concerning, I’m not too worried about the effect on emerged corn for several reasons:

1. The amount of corn emerged (and thus susceptible) across the state is low, especially in the areas with the coldest temperatures.
2. The growing point for corn is below the soil surface until the sixth leaf has emerged. The earliest emerged plants probably had only three to four leaves last weekend.
3. The short-term forecast calls for a warming trend with lots of sun. Many problems related to the May 28 frost in 1992 were related to the cool, damp weather that followed the freeze. Corn was very slow to recover and some did not survive.

Dr. Bob Nielsen, Extension agronomist at Purdue University, cautions that non-emerged corn plants may be affected by cold soil temperatures. He considers this more of a problem than the effect on emerged plants. Here is a quote from his news article:

“ … lethal cold temperatures (28^oF or less) can penetrate the upper inch or two of soil, especially dry surface soils, and kill plant tissue directly, including coleoptiles and growing points. Non-lethal injury by cold temperatures may cause deformed elongation of the mesocotyl or physical damage to the coleoptile in non-emerged seedlings, resulting in the proverbial ‘cork-screw’ symptom and subsequent leafing out underground.“

“ …. Given the risk of frost or chilling injury to young corn; it would behoove growers to monitor early planted fields over the next week to determine whether such injury has occurred and whether replanting may be warranted.“

Alfalfa seeded last spring or earlier (established) will recover, but rate of recovery will depend on amount of injury. Wait a couple days to determine how much, if any, of the plant tops were killed. Plant tops that remain green and upright will keep growing as normal. Handle these fields as you normally would manage them. However, fields with many plants that have the top 4 inches or more wilted, beginning to dry out, and/or becoming discolored will stop growing. Eventually, new shoots will develop -- some from branches on the main stem and some from the crown. Regrowth initiation can be delayed considerably, though, unless plants are harvested. If the entire field or substantial low sections of the field are injured, harvest will hasten recovery.

Alfalfa seeded last summer or fall will react similarly to established alfalfa except these young plants generally have fewer crown buds developed and available for rapid regrowth. Removal of existing plant material can put much stress on these plants; some may die and others will be susceptible to any subsequent stress such as insects, hail, and diseases. Usually it will be better to leave these plants uncut so they can use remaining green, healthy leaves to maintain plant health. Be patient for them to begin new growth.

Most seedings this spring should be safe. Young seedlings maintain cold tolerance well until they reach about the third trifoliolate leaf stage of growth. Also, heat from the soil often protects them from brief, cold temperatures. Seedlings that were frozen so that all trifoliolate leaves are discolored and dying will not regrow.

For preemergence herbicides to prevent weeds from surviving, they need to be incorporated into the soil with rainfall or mechanical incorporation. Often, herbicides may be applied to soil with residue on the surface, blocking the spray from soil contact. This herbicide will be ineffective until it is moved to the soil. Most Preemergence herbicides require 0.5 in of rainfall or greater for adequate incorporation. With mechanical incorporation, soil moisture must still be adequate for herbicide uptake and activity.

How long the herbicide can remain on the soil surface before incorporation and still remain adequately active depends on several factors, primarily the type of herbicide and the weather conditions. For example, Prowl is moderately volatile and should be incorporated within seven days before activity is lost. Hot temperatures and high winds may reduce this time. Many corn preemergence herbicides such as Dual, Bicep, Harness, Surpass, Balance, Frontier, and Atrazine are much less volatile and can remain on the soil surface longer without loss of activity. Under cool weather conditions, these herbicides can remain on the soil surface for two or more weeks before incorporation without significant loss. If rainfall has not occurred by the third week, other incorporation measures may be needed. Again, temperatures in the 80s with high winds will reduce this time.

If dry weather follows the application of a surface applied herbicide, weeds may emerge even though the herbicide is on the surface. If the weeds are more than 1 inch tall before rainfall occurs, most surface-applied herbicides will not control them.

For the most part, producers do not need to worry about incorporation of preemergence herbicides immediately after application. If you are in a dry situation, choose a herbicide that can remain unincorporated for two or more weeks and hope for rain.

Other factors, such as the time of velvetleaf emergence relative to crop emergence, can also influence the outcome of crop and weed competition. It’s logical to expect that later emerging weeds will be less competitive than weeds emerging with the crop. This knowledge of weed relative emergence can be used when making management decisions.

We conducted field studies in eastern Nebraska at two locations in 2002 and again in 2003 to determine the influence of soybean row spacing and relative time of weed emergence on velvetleaf and soybean growth and competition. This study is part of Shawn Hock’s research for his Master’s Degree.

Soybean was planted in 7.5- and 30-inch rows. Velvetleaf was hand planted at soybean planting (VP), emergence (VE), and 1st trifoliate (V1) stage. Observations were made throughout the growing season to determine the effects of row spacing and relative emergence on growth and development of both the crop and the weed.

Results from this study showed that velvetleaf produced much less dry matter and had about 60% less leaf area in narrow rows than in wide rows. Because the weed produced less dry matter and leaf area, it takes fewer resources from the crop. Velvetleaf emerging at the cotyledon stage (VC) of soybean produced 60% more dry matter than the velvetleaf that emerged at the V1 (1st trifoliate) stage of crop.

Soybean yields were higher in the narrow rows and when velvetleaf emerged later in the season. Soybean grown in 7.5-inch rows yielded 4 bushels more per acre than soybeans in 30-inch rows. Soybean yields were also reduced by 47%, 38%, and 15% when grown with velvetleaf emerging at the VC, V1, and V3 soybean stages, respectively.

A practical implication of this study is that planting narrow row soybeans will increase the crop competitiveness against weeds, including velvetleaf. Also, early season field scouting of weed emergence patterns relative to the crop growth stage can help determine management strategies. For example, earlier emerging weeds will require earlier weed removal.

This study was partially funded by a grant from the North Central Regional Weed Science Committee.

In most crop production fields there are many species of weeds and insects with different life cycles and survival mechanisms. It’s not likely that they can be managed by a single control measure. In reality, weeds and insects interact and affect not only each other and the crop, but also the efficacy of their respective management tactics. For example, insect-induced defoliation can significantly delay soybean canopy development and as a result, provide more sunlight for weeds to grow and compete with the crop.

This can directly affect subsequent weed management plans. Learning how insects and weeds interact with each other and the crop is essential in developing and integrating pest management strategies We are beginning the second year of a study of the interactions between weeds, insects and soybean. The main objective is to determine the critical time for weed removal as influenced by three levels of simulated insect defoliation -- 0%, 30%, and 60%. This study was conducted in summer 2003 and will be repeated in 2004 as part of Travis Gustafson’s research for his Master’s Degree. It is a collaborative project with the weed science and entomology programs at the Haskell Agricultural Laboratory near Concord.

Preliminary data suggest that the insect damage to the soybean leaf area indeed resulted in a need for earlier weed management. For example, with no insect damage to the soybean canopy, weeds could remain in the crop up to the V4 stage (third trifoliate) or about 20 days after crop emergence without significantly affecting the yields. However, at the 30% and 60% defoliation level, weeds should be removed by the V3 (17 days) and V1 (10 days) stages, respectively.

From a practical standpoint, this indicates that soybeans with 30%-60% leaf defoliation from insect damage actually do have a shorter weed control window and potentially fewer weed control options. This suggests that soybean leaf damage from bean leaf beetle feeding, for example, affects not only the final yield but also the timing of when weed control needs to be initiated in the growing season in order to prevent further yield losses.

This research also shows that the producer may have another tool to fight weeds in his soybean field – a good insecticide. If there is a particularly bad infestation of bean leaf beetle, spraying an insecticide to control the bean leaf beetle may actually widen the herbicide application window and increase weed control options for the producer.

The Nebraska Soybean Board helped fund this project.

Corn cutworms Cutworm damage

Some early season insects to watch for include various cutworm species, and, in southeast Nebraska, the southern corn leaf beetle. Cutworms can cause serious damage to corn in the first couple weeks after emergence, so it is important to scout fields for damage. Several species of cutworms attack corn. The severity and the area affected will vary greatly, depending on species involved, previous crop history, and weather conditions. Cutworms that attack corn can be divided into two general categories based on seasonal life cycles:

1. Black cutworms which do not overwinter in Nebraska, and
2. Dingy, claybacked, darksided, sandhills, pale western, and other species of cutworms, which overwinter as partially grown larvae in the soil.

Light traps and pheromone traps have been used to monitor the flight patterns and populations of black cutworms. Remember, the presence of moths in a trap only indicates potential problems and is no guarantee that extensive damage will occur. Trap counts are more useful in alerting growers and consultants as to when to begin scouting.

The weather of the last few weeks has been dominated by cool fronts moving in from the north and northwest. These conditions are NOT favorable for black cutworm establishment; however this week’s warmer temperature may be more favorable. Corn planted into heavy residue, fields with winter annuals, or fields planted into spring-killed alfalfa (that may attract egg-laying moths) have a slightly higher potential for cutworms.

When weeds are destroyed mechanically or by herbicides, they will feed on the newly emerging corn. Because most damage from cutworms occurs roughly in the first 7-10 days after emergence, growers should be on the lookout.

Cutworms that overwinter as larvae generally prefer to lay eggs in the fall in green vegetation such as small grain stubble, legumes, rye, and pasture. The eggs hatch and the larvae feed on available vegetation before overwintering. In spring, after the previous crop is removed and the corn emerges, the cutworms will transfer their feeding activity to the corn. Recent experience has been that corn planted into alfalfa that has been killed in the spring has a greater potential for cutworm problems.

Tillage has minimal effect on cutworm populations. If fields are tilled before black cutworms migrate, they may limit egg-laying in those fields. Cutworms already in the field may suffer some mortality by mechanical action, but there is no guarantee that tillage by itself will eliminate cutworm problems. Many cutworm problems have occurred in tilled fields.

It is extremely rare to experience cutworm problems in continuous corn. Corn stubble is not a preferred egg-laying site. Potential problems in continuous corn may result from the previous year’s late season flush of weeds, an interseeding of a fall cover crop such as rye, or a flush of winter annuals this spring, which can attract egg-laying moths.

Scouting and rescue treatments

Remember that early detection of a problem is essential because most of the cutting occurs within sevendays of plant emergence. Generally, a rescue treatment should be considered if 5% or more (an average of 1 plant or more in a set of 20) cutting is observed and the worms are one inch or less in length.

1. higher crop prices,
2. lower insecticide costs due to increased availability of effective generics, and
3. a “worry hangover” from the army cutworm problems seen earlier this year in alfalfa and wheat.

With seed-attacking insects like wireworms, there is no good rescue treatment, however, cutworms can be detected and treated to prevent damage if necessary. The cutworm complex in corn does not include the army cutworm, so despite the large amount of activity in alfalfa and wheat this spring, it has no direct correlation to what may happen in corn. The only possible connection is the indication that the cutworm species that overwinter as larvae had good survival conditions this year.

Also, products are being aggressively marketed as providing very long residual activity. Under ideal conditions, some materials may give 14, 21 or even more days of residual activity; however, in Nebraska with varying temperatures and soil conditions, a 7- to 10-day residual is more realistic.

The bottom line is that even if you treated for cutworms earlier, you still need to be scouting to make sure that black cutworms didn’t come in after the earlier treatments wore off. Even if light traps detect large flights of black cutworms, there is no way to know if they will choose your field to infest or bypass it for “greener pastures”.

If cutworms are present, they can cause serious damage to corn in the first few weeks after emergence so scout early and well and apply rescue treatments for cutworms as needed.

Southern corn leaf beetle

The adult corn leaf beetle overwinters in sheltered areas and becomes active in April. In addition to corn it may feed on weeds, including cocklebur. The adults are about 0.20 inch long, grey to dark brown and are often covered with soil particles, making them difficult to see. They hide in the soil during the day and are difficult to find. They feed on the stems of corn seedlings and the edges of leaves, producing a notched appearance. If abundant they may cause severe damage to seedling corn.

While some basic facts are known about the southern corn leaf beetle’s life cycle, there has been little biological research since the early 1900s. This beetle has one generation a year. The beetle lays eggs in the soil around the base of corn plants. The larvae hatch out in 6-10 days and feed on corn roots for about 10 weeks. Larvae pupate in the soil and adults emerge from mid July to August. Adults feed for a short while and then in late summer seek overwintering sites.

A Clearfield sunflower hybrid (center row) is tolerant to Beyond herbicide, but two conventional sunflower hybrids (two rows to the right of the Clearfield hybrid) are severely damaged by Beyond herbicide. The Express-tolerant sunflower hybrid (the row left of the Clearfield hybrid) shows a low level of cross-tolerance to Beyond herbicide, but still exhibits significant injury when treated with Beyond herbicide. UNL IANR Photo

Clearfield sunflower hybrids contain a gene that confers tolerance, not resistance, to the herbicide Beyond. Some slight crop injury (leaf yellowing and plant stunting) may occur after Beyond is applied to these hybrids, especially where overapplication occurs as in spray overlaps or field ends. Injured plants often recover quickly. Non-Clearfield hybrids will be killed if treated with Beyond.

Clearfield sunflower were developed through a traditional breeding technique known as mutagenesis and are not considered to be genetically modified organisms. Beyond herbicide is applied early postemergence to sunflower with two to eight leaves at a rate of 4 oz per acre. Weeds should be actively growing at the time of application and broadleaf weeds should be less than 3 inches tall. Grass weeds should have no more than four to five leaves. A nonionic surfactant and nitrogen based fertilizer must be added to the spray solution for optimum weed control.

It is recommended that a soil-applied grass herbicide, such as Prowl® or Dual Magnum®, be applied before Beyond is applied. Beyond will control many broadleaf weeds that are troublesome in Nebraska sunflower fields, including pigweed, kochia, Russian thistle, and nightshade; however, Beyond is an ALS-inhibitor and will not effectively control ALS-resistant kochia or Russian thistle. There is also some concern about the risk of transferring the gene conferring tolerance to Beyond from the commercial sunflower hybrid to weedy sunflower species such as common or prairie sunflower. This technology should be avoided in fields where weedy sunflower species are present.

In a dryland field study conducted at the High Plains Ag Lab near Sidney in 2001, all treatments containing Beyond herbicide provided excellent pigweed (tumble and redroot) and witchgrass control. Some injury was observed with all Beyond treatments. Most sunflower plants grew out of the injury within four weeks and no yield loss was observed.

In an irrigated study conducted near Scottsbluff in 2003, postemergence applications of Beyond caused the sunflower growing point to turn a light yellow, but plants recovered. Even though Beyond caused early season crop injury, sunflowers recovered by late June. Weed populations were dense and consisted of common lambsquarters, hairy nightshade, redroot pigweed, stinkgrass, and common purslane.

Preemergence application of Spartan plus Prowl herbicides provided excellent control of all weeds except hairy nightshade. Postemergence application of Beyond herbicide effectively controlled redroot pigweed and hairy nightshade. Combining a preemergence Prowl application with a postemergence Beyond application effectively controlled the weed spectrum present in this trial.

Although Beyond breaks down in the soil more quickly than some imidazolinone and sulfonylurea herbicides, there are still some crop rotation restrictions that need to be followed. Be sure to check the label when planning.

So what about cutting before plants bloom — or even before they form buds? Is this a realistic option? Being ready to cut healthy, vigorously growing alfalfa after it gets about fifteen inches tall has several advantages. Weather might be better than later in spring. You begin the harvest sequence early rather than waiting until all the alfalfa is ready at once. Some insect and disease problems can be reduced by early harvest. Most importantly, feed value can be very high. Plus, second cutting probably will be ready before summer heat lowers its forage quality.

One disadvantage, however, is that yield will be lower from this early cut, although much of it will be made up in later harvests. Also, regrowth for second harvest probably will be slower than if alfalfa had been cut at a more advanced stage of growth, especially if your alfalfa experienced winter injury this year. And you must be sure to allow a longer than normal recovery after either the first or the second cutting if you want to maintain long-term stands.

Both common ragweed, which is an annual, and western ragweed, which is a perennial, can be held in check using similar methods. Still, common ragweed is controlled more easily with grazing management or herbicides than western ragweed.

Research and observations show that ragweed problems are worst in pastures that fail to maintain grass competition with a full leaf canopy in late May through late June. If you had ragweed problems in recent years, look for tiny plants or seedlings underneath your grass during the next couple of weeks. Heavy grazing or haying during this time opens up the grass sward, allowing seedlings and small plants to grow rapidly.

Any management practice that develops and maintains a dense canopy at this time helps reduce problems with ragweed. These practices can include fertilizing to increase grass growth, seeding to thicken stands, and most importantly, avoiding heavy grazing in areas where ragweed has been a problem.

If you do graze heavily or cut hay, one quart of 2,4-D or Grazon after grazing or cutting gives good control of ragweed seedlings and small plants. If you miss opportunities for spring control, shredding in September can reduce seed production.

It takes time and a well-planned approach to control ragweed, but with good grazing, some spraying, and timely shredding it can be done.

I witnessed how not controlling winter annuals in the fall or early spring depletes soil moisture. Several years ago Martin and Kappler had planted henbit and pennycress in a plot in which we were hoping to plant no-till corn this year. These two weed species had not been controlled prior to our attempt to plant. Because of the lack of rainfall this spring these two weeds had zapped most of the soil moisture from the seed zone. It was so dry and hard that our 7200 John Deere planter could not penetrate the soil deep enough for proper seed placement. The plot area near this plot had been treated for winter annuals this spring. At this site we had irrigated corn stalks in which half of the area was disked this spring and the other half no-tilled. The no-till area had adequate soil moisture and planter penetration and seed placement were not an issue. In the tilled area the soil was dried out and hard and we had to set our seed setting deeper to obtain proper seed placement.

After seeing, feeling and experiencing the difference in the soil conditions, I asked myself how many farmers have actually experienced what I just did and still continued to till the soil. Of course what I just experienced was something I witnessed long ago in my career. It reaffirmed what I already new. I will need to irrigate or hope for a rain soon in the areas where weeds were not controlled or spring tillage was done. Tillage and weeds....priceless!

John Wilson, Extension educator in Burt County: Frost nipped alfalfa and early emerged corn Monday morning, but should not cause extensive problems as the corn growing point was below the soil. We had a significant catch of black cutworm moths April 30. Area farmers should start scouting for cutworm feeding approximately 300 GDDs after the moth catch.

Ralph Anderson, former Extension educator in Buffalo County, now at Ward Laboratories in Kearney: Corn planting in central Nebraska has progressed fairly well. First planting corn can be “rowed” easily now. We have not seen any severe crusting problems, but producers need to check their fields.

Many farmers are wrapping up corn planting and preparing to plant soybeans. Sunday night’s low temperatures reminded us not to get too anxious. We certainly haven’t had excess moisture, but we probably have an adequate amount to germinate the crop and activate the herbicides.

Wheat is looking fairly clean so far, but reports of disease in the south and the strong south winds may change that rapidly.

We have seen some yellow streaks in wheat, but tissue tests on those we checked indicated sulfur deficiency, rather than nitrogen.

Paul Hay, Extension educator in Gage County: It is unlikely that the 27-28oF frost on May 3 did any damage to our southeast Nebraska wheat crop which is in the boot stage. Corn was nipped back but will recover fine. Some alfalfa weevil pressure, but it’s light, and some powdery mildew on wheat. Producers are well into soybean planting this week.

Terry Gompert, Extension educator in Knox County: We are now 5 inches short of rain this season. In spite of that the grass, alfalfa and oats look good except where cutworms were not controlled. This is the first year that I can remember when oats were killed by cutworms. Cutworms have even been found in native range and thousands of acres of alfalfa have been treated the past three weeks.

Corn planting is 60% complete and soybean planting has started. Pastures started out well but growth has slowed in the past week. Cool temperatures and lack of rain are starting to take a toll.

Jennifer Chaky, Extension educator, UNL Pest and Plant Disease Clinic: Following is a list of some of the injury we diagnosed in the clinic in April:

Alfalfa - chemical injury (Kearney County), spring black stem and soil compaction (Saunders County); Wheat - soil borne wheat mosaic virus (Clay and Gage counties), wheat spindle streak mosaic virus (Gage County), wheat streak mosaic virus (Chase County), Nitrogen deficiency (Chase County) and Tan Spot (Red Willow County). In addition to the virus problems observed on several wheat samples, powdery mildew has been found, especially on southeast Nebraska wheat.

David Keith, Extension entomologist: When you’re working outside this spring and summer, remember to check for ticks. This time of year, they’re everywhere. When entering tick-infested areas, wear long sleeves and trousers and tuck pant legs into socks. When you return home, have someone examine you for ticks, especially around the ears and nape of the neck, use a fine-toothed comb, and take a hot, soapy shower.

Repellents also can help. Treat the outside of clothing lightly and use as little as possible directly on skin. Too many people overdo such applications. High amounts of highly concentrated DEET products can be hazardous to sensitive individuals, small children and older adults. Using products with lower DEET concentrations will help. Permethrin is another choice for treating exterior clothing.

Some species of mosquitoes, another pest, have been out since February and others are appearing now, generated from scattered breeding areas and artificial containers with stagnant standing water. Since our rainfall has been light so far, we do not have high numbers, but we will be keeping an eye on these throughout the spring and into the summer, especially due to the concerns regarding the West Nile Virus. Remember that most early season mosquitoes in Nebraska are not culex mosquitoes, the group most responsible for transmitting the West Nile Virus.

June 16, Wednesday, 3 p.m. (MDT), Sidney, High Plains Agricultural Laboratory

June 17, Thursday, 8:30 a.m. (MDT), Scottsbluff, Panhandle Research and Extension Center

June 22, Tuesday, 9 a.m., Clay Center, South Central Ag Lab

June 23, Wednesday, 9 a.m., Lincoln, Havelock Research Farm

June 24, Thursday, 1 p.m., Concord, Haskell Ag Lab