Integrated Pest & Crop Management Newsletter University of Missouri-Columbia Vol. 16, No. 4 Article 1 of 7 April 7, 2006 Wheat Disease Update- April 3, 2006 By Laura Sweets There have been a few reports of virus-like symptoms on winter wheat so far this spring. See last month’s issue of the Integrated Pest and Crop Management Newsletter for more detailed information on the common virus diseases of winter wheat in Missouri. There have also been a few reports of leaf rust and stripe rust on wheat in the southern United States. It is a little early for these diseases to be showing in Missouri, but with the recent periods of wet weather, it would be wise to begin scouting wheat for leaf rust, stripe rust and Septoria leaf blotch. Leaf rust starts as small yellow to light-green flecks on the upper leaf surfaces. These flecks develop into the small, circular to oval-shaped, orange-red pustules characteristic of leaf rust. Stripe rust may develop earlier in the season than leaf rust. The pustules of stripe rust are yellow to yellowish-red, and occur in obvious stripes or streaks running lengthwise on the wheat leaves. Septoria leaf blotch may begin as light yellow flecks or streaks on the lowest leaves. These flecks expand into yellow to reddish-brown, irregularly shaped blotches. Dark brown specks (fruiting bodies or pycnidia of the causal fungus) may be scattered within the centers of mature lesions. Now is the time to be scouting fields to determine which leaf diseases are present as well as the level of their severity. It would be unusual for foliar fungicides to be applied this early in the season, but knowing what is showing up and the incidence and severity of these diseases is crucial in making management decisions later in the season. Laura Sweets Ag Ext.-Plant Sciences 573-884-7307 ********************************************************************* Soybean Rust Update- April 3, 2006 By Laura Sweets Scouting for soybean rust, primarily on kudzu, continues in the southern states. Kudzu is beginning to green up across the southern United States and scouting efforts in those areas has intensified. Thus far, soybean rust has been confirmed on kudzu in eleven Florida counties, four Georgia counties and five Alabama counties as well as on soybean plants (since harvested) in one Texas county. As of April 3, 2006, there have not been any reports of soybean rust on newly planted soybeans. Sentinel plots have been planted in many of the southern states and some are beginning to emerge. The USDA Public Soybean Rust Web site at www.sbrusa.net is being updated on a regular basis, and is a good source for information on reports of soybean rust in the southern United States. Missouri will be participating in the sentinel plot program again this season. However, this early in the season, none of our sentinel plots have been planted, kudzu is still dormant and scouting (except for observations on kudzu growth) hasn’t begun. It will be particularly interesting and important to follow reports from Texas and Mexico during the 2006 season. Texas: The soybean rust pathogen was confirmed on kudzu leaves collected from a site near Dayton, Texas (just northeast of Houston in Liberty County, Texas) on November 2, 2005. Soybean rust was not found in soybean fields near this kudzu patch. And on January 17, Tom Isakeit, Extension Plant Pathologist with Texas A & M University, reported that the kudzu patch in Liberty County had been completely killed back. Then in February of 2006, soybean rust was confirmed on plants in a one-acre plot in Weslaco, Texas (Hidalgo County just north of the Mexican border). The plot was part of an irrigation study, and most of the plants in the field were mature by February 14. Soybean rust was found on some younger plants along the edge of the field. The plot was harvested not long after the rust was confirmed. At this point the kudzu in Dayton, Texas (Liberty County) has been developing new growth but has not shown symptoms of soybean rust on the foliage. Sentinel plots that have emerged have not shown any symptoms of soybean rust. Mexico: In February it was announced that soybean rust had been confirmed on leaves collected in October 2005 from the variety Huasteca 400. The leaves were collected at harvest and had symptoms and signs of a low incidence of soybean rust. Confirmations of soybean rust on soybeans were made from two locations, Tamuin in the State of San Luis Potosi and Altamira, in the state of Tamaulipas (northeastern part of Mexico). Samples were collected as the fields were being harvested and there have not been additional reports of soybean rust from Mexico. Again, for 2006 it is important for soybean producers in Missouri to be aware of disease development and weather patterns in the southern United States; to scout fields and be aware of results from the sentinel plot system in southern states, states close to Missouri and in Missouri; and to be prepared to take prompt action if a risk of soybean rust develops. Laura Sweets Ag Ext.-Plant Sciences 573-884-7307 ******************************************************************** High Potential for Flea Beetle Problems in Field Corn? By Wayne Bailey Mild winter temperatures during the months of December, January and February indicate the potential for high populations of flea beetle in most regions of Missouri. In our model, the potential for flea beetle damage is calculated by adding together the average daily winter temperatures for the months of December, January and February. If the average monthly temperatures for these months add to less than 90 degrees Fahrenheit, then the risk of economic flea beetle infestations is low. If the total is between 90 degrees and 100 degrees, moderate flea beetle damage can be expected. Heavy damage is possible if the three monthly averages total 100 degrees or more. Data from the 17 Commercial Agricultural Weather Stations located around the state are summarized by regions of the state and specific counties in the following table. Average monthly temperatures are given in degrees Fahrenheit. The following information has been provided by Jim Jarman, regional agronomy specialist. My thanks to Jim for his efforts and contribution to the newsletter. 2006 Corn Flea Beetle Predictions Table 1 For Missouri County, University of Missouri Commercial | Sum of average winter Agriculture automated weather station location | temperatures (Degrees | Fahrenheit) Northern Missouri Region Average Temperature | 96.08 _________________________________________________|____________ Atchison County, Graves Memorial Plots (3 miles | north of Corning) | 97.80 _________________________________________________|____________ Gentry County, Hundley-Whaley Farm (Albany) | 93.60 _________________________________________________|____________ Linn County, Forage Systems Research Center | (Linneus) | 95.90 _________________________________________________|____________ Knox County, Greenley Memorial Center (1 mile | east of Novelty) | 93.70 _________________________________________________|____________ Buchanan County, Buchanan County Extension | Center (St. Joseph) | 99.40 _________________________________________________|____________ Central Missouri Region Average Temperatures | 104.44 _________________________________________________|____________ Audrain County, 6 miles northwest of Auxvasse | 101.60 _________________________________________________|____________ Chariton County, 4 miles west of Brunswick | 98.60 _________________________________________________|____________ Boone County, South Farms (4 miles southeast of | Columbia) | 104.00 _________________________________________________|____________ Boone County, Sanborn Field (University of | Missouri-Columbia) | 107.30 _________________________________________________|____________ Monroe County, Monroe City (Monroe City Airport) | 103.40 _________________________________________________|____________ Morgan County, Versailles R-II Outdoor Classroom | 110.10 _________________________________________________|____________ Pettis County, Green Ridge R-VIII School District| 105.80 _________________________________________________|____________ South West Missouri Region Temperature | 112.30 _________________________________________________|____________ Barton County, Lamar (Barton County Electrical | Cooperative) | 112.30 _________________________________________________|____________ South Central (Ozark) Missouri Region Average | Temperatures | 106.10 _________________________________________________|____________ Crawford County, Wurdack Farm (2 miles east of | Cook Station) | 109.90 _________________________________________________|____________ Shannon County Alley Springs (Ozark National | Scenic Riverways Network) | 101.60 _________________________________________________|____________ Shannon County Round Springs (Ozark National | Scenic Riverways Network) | 106.80 _________________________________________________|____________ South East Missouri (Bootheel) Region Average | Temperatures | 119.36 _________________________________________________|____________ Cape Girardeau County, Delta | 112.00 _________________________________________________|____________ Dunklin County, Cardwell | 121.60 _________________________________________________|____________ Dunklin County, Rice Farm (1 mile east of | Glennonville) | 119.80 _________________________________________________|____________ Dunklin County, Rhodes Memorial Research Farm | (north of Clarkton) | 118.00 _________________________________________________|____________ Mississippi County, (5 miles south of Charleston)| 117.00 _________________________________________________|____________ Pemiscot County, Delta Center (Portageville) | 121.70 _________________________________________________|____________ Pemiscot County, (6 miles west of Steele) | 122.60 _________________________________________________|____________ Pemiscot County, Lee Farm (5 miles southeast of | Portageville, MO) | 122.20 _________________________________________________|____________ Biology/ Damage Flea beetles are small, dark, jumping beetles which overwinter as adults. In early spring, they move to seedling corn and feed on plant foliage from the time of plant emergence through about the fourth-leaf stage of growth. Adult beetles strip the chlorophyll layer (green tissue) from the surface of seedling corn leaves resulting in the formation of "window panes" or translucent areas in leaf surfaces. Damage is often seen as translucent tracks or lines that run parallel to the veins of the corn leaf. Heavy flea beetle infestations cause plants to look "tattered" and wilted, similar to the type of injury caused to seedling corn when blasted by blowing sand. The most injurious flea beetle attacking corn is the corn or maize flea beetle. Typically, infestations are most severe in years where mild winters allow for increased survival of adults, and cool temperatures and drought conditions during spring result in slowed growth of corn plants. Flea beetles may transmit Stewart’s wilt (a bacterial wilt) to corn, although most field corn has resistance to this plant pathogen. The economic threshold for implementation of control methods for flea beetles in field corn is an average of five or more beetles per corn seedling up through the fourth-leaf stage of development. To scout for flea beetles, examine corn plants for feeding damage and determine the average number of flea beetles present per corn plant. This is most readily accomplished in the early morning or late afternoon by walking slowly through the field and counting beetles as they feed. Remember, flea beetles are easily recognized by their jumping ability similar to grasshoppers. Management Options Although the model predicts high populations of flea beetle for most areas of the state, a couple factors may limit flea beetle numbers in the 2006 season. First, adult beetle mortality may be higher than predicted due to several rapid changes in temperatures during winter months and this spring. A second factor may be that the widespread use of seed treatments for corn during the past few years may be suppressing flea beetle problems statewide, similar to what Bt corn has done to the European corn borer populations throughout the Midwest. Regardless of predictions and insecticide use, producers are encouraged to scout seedling corn for the presence of flea beetle this spring. If an economic population is found, an effective management option for flea beetle is the use of foliar applied insecticide rescue treatments. Several insecticides are labeled for this use once the economic threshold has been reached or exceeded. Cruiser and Poncho seed treatments also provide good protection from this pest due to their systemic activity in seedling foliage. First Capture Of Black Cutworm Moths The first capture of BCW moths in central Missouri occurred in mid-March. Moth captures have been low since that time due to several days of cold temperatures and very high winds preventing moth movement over the landscape. Captures of moths are expected to increase over the next few days as warmer temperatures are predicted. Visit the IPM Web site at http://ipm.missouri.edu/pestmonitoring/blackcutworm/index. htm for additional information on black cutworm activity and predictions for first cutting of field corn by 4th instar larvae. Insecticides And Rates Labeled For Flea Beetle Management Used As Rescue Treatment On Field Corn Include The Following: Flea | | | 6.4 to |Over| Beetles |Permethrin | Ambush* | 12.8 fl |row | | | | oz | | | | | 5.8 to | | |Esfenvalerate | Asana XL* | 9.6 fl | | | | | oz | | | | | 0.8 to | | |Cyfluthrin | Baythroid 2*| 1.6 fl | | | | | oz | | | | | 2.1 to | | |Bifenthrin | Capture 2EC*| 6.4 fl | | | | | oz | | Treatment is | | | 2.1 to | | justified when |Bifenthrin | Fanfare 2EC*| 6.4 fl | | 5 or more | | | oz | | beetles per | | | | | plant are |Chlorpyrifos | Lorsban 4E* | 1 to 2 | | present or | | | pt | | when seedling | | | 2.72 to | | plants are |Zeta-cypermethrin | Mustang Max*| 4 fl oz | | being severely | | | 1 to 2 | | damage or |Chlorpyrifos | Nufos 4E* | pt | | killed and | | | | | beetles are |Microencapsulated | Penncap-M* | 2 to 3 | | present. |Methyl parathion | | pt | | | | | | | |Permethrin | Pounce | 4 to 8 | | | | 3.2EC* | fl oz | | | | | 2.56 to | | |Gamma-cyhalothrin | Proaxis* | 3.84 fl | | | | | oz | | | | | | | |Carbaryl | Sevin XLR | 1 to 3 | | | | Plus | pt | | | | | 2.56 to | | |Lambda-cyhalothrin | Warrior* | 3.84 fl | | | | | oz | | |* indicates restricte|d use pesticide |(RUP) | | Treatment is justified when five or more beetles per plant are present or when seedling plants are being severely damage or killed and beetles are present. Be sure to read and follow all label directions, precautions, and restrictions. Wayne Bailey 573-882-2838 office or 573-864-9905 cell ********************************************************************* Complementary equipment yields ultimate control and improved efficiency By Bill Casady If you have made the choice to purchase equipment that works well together, then let me be the first to compliment you on your choice of equipment complement. But just what does it mean to choose a good equipment complement? The phrase "equipment complement" can simply imply that you have enough of every piece of equipment so that you can get the job done. But the word "complement" is often used to describe a "good match." Among the definitions of complement in a recent edition of one of Merriam-Webster's Dictionaries is "something that completes and makes perfect." The word complementary can mean that there is a "precise pairing." Perfectly-Matched Tractors And Implements Are Efficient When a tractor is matched to the implement that it pulls, the engine will perform best and fuel efficiency will be maximized. The "precise pairing" of a tractor and an implement will allow the implement to be pulled through the field at an appropriate speed and under a load that will allow the tractor to perform with maximum efficiency. The investment made in both the tractor and the implement is also likely to provide maximum returns for that investment. A tractor that is too large will result in poorer fuel efficiency. By selecting a higher gear and throttling back, then fuel efficiency can be increased. The tractor may still be heavier than it needs to be; and that can cause more "deep compaction" than necessary. However, you can 1) remove extra weight and 2) remove some air from the tires. Together, these steps will increase performance and reduce compaction. A tractor that is too small will be unable to pull the implement through the field without gearing way down. A fully loaded tractor at slow speeds can cause premature drive-train wear. The tires will likely be smaller and more weight will be needed. The extra weight will cause more surface compaction; tire pressures will have to be increased, and fuel may be wasted due to the extra slip that is bound to occur under these conditions. There's little that can be done to improve the situation when the implement is just too large for the tractor. Matched Width Planters, Combines, Sprayers, And Other Equipment Allow Controlled Traffic And Can Control Compaction The obvious need for matching is for row spacing of planters and combines to be equal, or at least of some multiple, so that crooked driving doesn't cause problems for harvesting row crops. As we begin to adopt precision guidance technology, we could get around the problem as long as we can control the spacing of all rows to within an inch. Better yet, though, precision guidance and a properly selected equipment complement can help keep load bearing tires in the same tracks for every field operation. Controlled traffic is not only possible, but commonplace in some parts of the world. Controlled traffic can be accomplished by dead reckoning, but we are rapidly approaching an era where precise guidance will become not only very affordable, but a commonplace accessory. This technology will make it a snap to travel only in permanently compacted lanes. Equipment purchases should be planned so that the width of each piece of equipment is precisely paired with other equipment so that all tractors and combines use the same system of tracks. Permanently compacted lanes, often called "tram lines," have many advantages and very few or no disadvantages as long as we are prepared. Permanently compacted tracks can sometimes even provide a firm surface for us to be in the field with a combine even when the weather did not cooperate. Making ruts in the name of a timely harvest be become a thing of the past. I like that idea. The firm surface of permanent lanes also helps us transmit power to the ground more efficiently, and that reduces fuel consumption. To farmers, the soil is everything. Under the current system, if you can call it that, nearly every inch of the soil is eventually trampled by a heavily loaded tire over a period of several years. Permanent lanes eliminate that practice and as much as 80 to 90 percent of the soil will never have the life squeezed out of it again. I think it is a choice and I think controlled traffic is a good choice. Continue to squeeze the life out of the soil periodically or give it a fair chance to perform in its natural state. Could compaction problems become just a memory? Bill Casady (573) 882-4370 ********************************************************************* Influence of Fall and Spring Herbicide Applications on Soil Temperature and Moisture in No-Till Soybean: 1st Year Results By Nick Monnig and Kevin Bradley In last month’s newsletter we discussed the effects of fall herbicide applications on soil temperature and moisture at the time of corn planting. In that article, we indicated that some believe that fall herbicide applications can lead to increased soil temperatures at planting and that these applications will also allow the soil to dry out faster by the time of spring planting. However, we found no differences in soil temperature or moisture between fall or spring herbicide applications with regard to corn planting. In this article, we will discuss the first year of results from experiments that were conducted to determine the effects of fall and early spring herbicide applications on soil temperature and moisture at the time of soybean planting. In the fall of 2004, we established three field experiments in central, northeast, and northwest Missouri. In both experiments, herbicide applications were made in the fall, 60, 30, and 7 days prior to soybean planting. Each timing consisted of the following four treatments: 3.5 oz. Canopy XL plus 1 pt 2,4-D ester per acre, 2.2 oz Canopy EX plus 1 pt 2,4-D ester per acre, 28 fl ozs Roundup Original Max plus 1 pt 2,4- D ester per acre, and an untreated control. Soil temperature thermometers were placed at a one-inch depth to record soil temperature every day from March 1 to May 31. Soil moisture readings were recorded every two weeks at a 4 ½ inch depth beginning in early March and continuing until two weeks after planting. Measurements of soil temperature at planting revealed that the untreated plots ranged from two to four degrees warmer than any of the herbicide-treated plots within each of the four application timings. However, two weeks after planting the untreated plots ranged from seven to 13 degrees higher in soil temperature than the herbicidetreated plots, regardless of the specific application timing. These results are actually opposite of what many might have expected (including us). Plots with dense stands of winter annual weeds left uncontrolled actually resulted in higher soil temperatures at planting and at two weeks after planting than in plots that were free of winter annual weeds due to the fall or early spring herbicide treatments. We believe that these differences might be explained by the differences in soil moisture that were observed in these experiments. At the time of soybean planting, the untreated ranged from having volumetric water content levels similar to the herbicidetreated plots (central location), to having two percent less volumetric water content at the northern locations. However, the major differences in soil moisture came two weeks after planting, which as discussed previously corresponded to a period where major differences in soil temperature were also observed. Two weeks after planting the untreated plots had a volumetric water content which was seven percent less than the herbicide treated plots at all three locations (Figure 1). We attribute this response to the presence of dense stands of winter annual weeds in the untreated compared to the herbicidetreated plots, which served to "wick" significant amounts of moisture from these areas. Lower soil moisture present in the untreated plots two weeks after planting correlated with higher soil temperatures at this same time. We believe that the untreated plots may have had higher soil temperatures because they had less moisture present in the soil, which enabled them to warm up more rapidly when compared to the herbicidetreated plots. Another factor which is likely to affect the amount of soil moisture present in untreated versus herbicide-treated fields is the amount of rainfall received throughout the spring. It is likely that lower amounts of rainfall in the spring will lead to larger differences in soil moisture between untreated and herbicide-treated fields. In springs where we have excessive amounts of rainfall, these differences may be minor or nonexistent. Overall, after one year of data our field studies have not proven that fall herbicide applications either increase soil temperature or decrease soil moisture at soybean planting, as some have speculated. However, our results have shown that the removal of winter annual weeds with fall or early spring herbicide applications can cause lower soil temperatures and higher soil moisture when compared to untreated areas. In our experiments, this response was most noticeable at two weeks after planting. Our first year studies suggest that winter annual weed removal may have a significant impact on soil conditions. Additional experiments were initiated in the fall of 2005 and will continue through 2006 to determine whether or not these results are consistent across years. By Nick Monnig and Kevin Bradley 573-882-4039 -******************************************************************** Alfalfa Weevil Problems Common in Alfalfa Fields in Southern Missouri By Wayne Bailey Alfalfa weevil larvae are present in many south Missouri fields with some alfalfa fields requiring insecticide applications for control of weevil larvae. Producers in southern and central Missouri counties are encouraged to scout for weevils and damage at this time. Alfalfa weevil larvae grow through four instars or worm stages as they develop into adults. First observed damage from this pest is usually seen as small feeding holes in alfalfa leaflets caused by initial feeding of first instars inside plant terminals. As the leaf material grows out of the plant terminal, the damage becomes visible. Second through fourth instars feed directly on leaf tissue with defoliation increasing as the size of larvae increase. Although most larvae in southern Missouri are small to medium in size, economic damage has resulted in the need for use of control measures such as an insecticide application. Damage in more northern parts of Missouri are expected as eggs continue to hatch and larvae develop. Although numbers of alfalfa weevil eggs are high in most areas of the state, high egg numbers do not always result in high numbers of larvae or heavy yield loss of alfalfa. In years with cool, wet springs an insect fungal pathogen, Zoophthora phytonomi, often infects and quickly kills alfalfa weevil larvae. Recent rainfall and cool nighttime temperatures throughout the state certainly increase the potential for the development of this fungal pathogen. Infect alfalfa weevil larvae change from their normal green to more yellow in color, become slowed in movement, and generally die within 2-3 days after infection occurs. At present the fungal pathogen has not been found infecting alfalfa weevil larvae in the state. Scouting for alfalfa weevil is accomplished by randomly collecting 50 alfalfa stems (10 stems at 5 different locations) and tapping them into a white bucket. Larvae will generally be dislodged by this action and allow for an average number of larvae per alfalfa stem to be calculated. Caution should be used when collecting stems as larvae can be easily dislodged from the growing tip of the plant stem by rough handling. It is recommended that the top of the alfalfa stem be cupped in one hand while the plant stem is removed by cutting with a knife near the base of the stem. If an average of one or more larvae per stem is found (50 or more larvae per 50 stems), then the economic threshold has been reached and control is justified. Management Options The main management option for early infestations of alfalfa weevil larvae on small alfalfa is an application of a labeled insecticide. Early harvest of the alfalfa by either machine or livestock may be viable options for some producers in Missouri. If early harvest of alfalfa by machine is selected as a control strategy, then the crop is harvested approximately 7-10 prior to the normal plant growth stage of 1/10nth bloom. Data from a Missouri study indicate that alfalfa weevil larval numbers may be reduced by about 98 percent with mechanical harvest and about 90 percent by cattle grazing in a management intensive grazing system. Producers using grazing as a control strategy must be aware of the bloat risk to cattle grazing green alfalfa and risk to the alfalfa stand due to trampling during wet conditions. If an insecticide application is selected, a list of insecticides recommended for alfalfa weevil control follows. Rates are given as amount of product applied per acre. The pre-harvest interval lists the minimum number of days before harvest that an insecticide application can be applied. If an insecticide application is selected, a list of insecticides recommended for larval alfalfa weevil control follows. Be sure to read and follow all label directions, restrictions and precautions. Insecticides recommended for alfalfa weevil larval control on Alfalfa Chemical Name | Product Name | Rates Amount of | Preharvest Interval | | Product | (PHI) Cyfluthrin | Baythroid 2* | 1.6 to 2.8 fl |7 days | | oz/acre | Methyl Parathion| Chemnova Methyl 4EC*| See label rates |15 days Carbofuran | Furadan 4F* | 1/2 to 2 pts / |7 - 28 days | | acre |depending on rate Phosmet | Imidan 70W* | 1.3 lbs. / acre |7 days Chlorpyrifos | Lorsban 4E* | 1 to 2 pts / |14 - 21 days | | acre | Chlorpyrifos | Nufos 4E* | 1 to 2 pts / |14 - 21 days | | acre | Chlorpyrifos | several | See specific |See specific label | formulations* | labels | Malathion | Malathion | 1.25 lb a.i. / |See specific label | | acre |for rates/PHI Zetacypermethrin| Mustang Max* | 2.24 to 4.0 fl |3 days | | oz / acre | Permethrin | Pounce 3.2EC* | See label rates |Variable results in | | |MO trials | Ambush 2E* | See label rates |Variable results in | | |MO trials Gammacyhalothrin| Proaxis* | 2.56 to 3.84 fl |1 day forage, 7 day | | oz / acre |hay Lambdacyhalothrin|Warrior* |2.56 to 3.84 fl 1| day forage, 7 day | | oz / acre |hay Lambdacyhalothrin|Several |See specific S|ee specific labels | formulations* | labels | * indicates Restricted Use a.i. = active ingredient Scattered Problems With Cowpea And Pea Aphids In Alfalfa Have Been Reported From Southwest Missouri The cowpea aphid is a dark colored to black aphid which was first found in Missouri in the early 1990s. This insect tends to feed on the tips of alfalfa during early spring and can cause yellowing of plant leaflets from the bottom upward. Although no formal economic threshold is available, the one used for pea aphid would be a good starting point. If an average of 50 or more aphids per alfalfa stem are present, then control may be justified. If plants are under drought stress or growing slowly due to cool weather, then the threshold number would be reduced. Treatment also may be justified if plants are yellowing and aphids are present. The pea aphid is larger, green in color, and can be identified by a dark band around the base of the antennal segments. Pea aphid problems are most severe on slow growing alfalfa during early spring. Later infestations of the pea aphid during spring may cause economic problems, but generally plants 10 inches or more in height can withstand higher numbers of aphids. As with cowpea aphids, pea aphids can cause yellowing and sometimes wilting of plants due to their removal of plant juices. The tables that follow list insecticides labeled for control of these pests in Missouri. Be sure to follow all label directions, precautions, and restrictions. Insecticides recommended for cowpea aphid control on alfalfa Chemical Name | Product Name | Rates (Amount |Preharvest Interval | | of Product) | (PHI) Cyfluthrin | Baythroid 2* | 2.8 fl oz / |7 days | | acre | | | | Methyl Parathion | Chemnova Methyl | See specific |15 days | 4EC* | label | | | | Chlorpyrifos | Lorsban 4E* | 1 to 2 pts / |14 - 21 days | | acre | | | | Chlorpyrifos | Nufos 4E* | 1 to 2 pts / |14 - 21 days | | acre | | | | Chlorpyrifos | Several | See specific |See specific label | formulations* | labels | | | | Malathion | Malathion | 1 lb a.i. / |See specific label | | acre |for rates/PHI | | | Zetacypermethrin | Mustang Max* | 2.24 to 4.0 fl |3 days | | oz / acre | | | | Gammacyhalothrin | Proaxis* | 2.56 to 3.84 fl |1 day forage, 7 day | | oz / acre |hay | | | Lambdacyhalothrin| Warrior* | 2.56 to 3.84 fl |1 day forage, 7 day | | oz / acre |hay | | | Lambdacyhalothrin| Several | See specific |See specific labels | formulations* | labels | * indicates Restricted Use a.i. = active ingredient Insecticides recommended for pea aphid control on alfalfa Chemical Name | Product Name | Rates (Amount of| Preharvest | | Product) | Interval (PHI) Cyfluthrin | Baythroid 2* | 2.8 fl oz / acre| 7 days Methyl Parathion | Chemnova Methyl | See specific | 15 days | 4EC* | label | Dimethoate | Dimethoate; Dimate | See specific | See specific label | | label | Chlorpyrifos | Lorsban 4E* | 1 to 2 pts / | 14 - 21 days | | acre | Chlorpyrifos | Nufos 4E* | 1 to 2 pts / | 14 - 21 days | | acre | Chlorpyrifos | Several | See specific | See specific label | formulations* | labels | Malathion | Malathion | 1 lb to 1.25 | See specific label | | a.i. / acre | for rates/PHI Zetacypermethrin | Mustang Max* | 2.24 to 4.0 fl | 3 days | | oz / acre | Gammacyhalothrin | Proaxis* | 2.56 to 3.84 fl | 1 day forage, 7 | | oz / acre | day hay Lambdacyhalothrin| Warrior* | 2.56 to 3.84 fl | 1 day forage, 7 | | oz / acre | day hay Lambdacyhalothrin| Several | See specific | See specific | formulations* | labels | labels * indicates Restricted Use a.i. = active ingredient Wayne Bailey 573/882-2838 office or 573/864-9905 cell ********************************************************************* Weather Data for the Week Ending April 2, 2006 By Pat Guinan -------------------------------------------------------------------------------- | Monthly | Growing Weekly Temperature (deg. F) |Precip (in.)|Degree Days^ -----------------------------|------------|------------ Ext- Ext- Depart| Depart|Accum Deprt Avg.Avg. reme reme from |Mar 1- from |since from Station County Max.Min. High Low Mean avg. |Mar 14 avg. |Apr 1 avg ------------------------------------------------------|------------|------------ Corning Atchison 64 41 73 31 52 +5 | 1.81 -0.53| 9 +9 St. Joseph Buchanan 63 43 70 35 52 +4 | 2.13 -0.04| 13 +12 Brunswick Chariton 64 43 76 32 53 +4 | 2.99 +0.55| 16 +15 Albany Gentry 63 41 71 33 51 +3 | 1.43 -1.22| 7 +7 Auxvasse Audrain 66 44 78 33 54 +5 | 4.81 +1.96| 18 +17 Columbia Boone 67 44 80 33 55 +5 | 3.73 +0.75| 22 +19 Sanborn Field Boone 67 46 80 35 56 +6 | 3.11 +0.16| 24 +20 Novelty Knox 61 43 76 37 51 +3 | 2.83 +0.36| 7 +7 Linneus Linn 62 42 75 32 52 +4 | 3.54 +1.20| 11 +11 Monroe City Monroe * * * * * * | * * | * * Versailles Morgan 69 46 80 34 57 +6 | 3.27 +0.14| 27 +21 Green Ridge Pettis 67 44 77 34 55 +7 | 2.63 -0.31| 23 +23 Lamar Barton 70 44 76 31 58 +7 | 2.09 -1.44| 27 +22 Cook Station Crawford 70 41 80 26 56 +4 | 4.58 +0.83| 25 +21 Alley Spring Shannon 72 38 82 25 56 +5 | 5.18 +1.21| 28 +24 Round Spring Shannon 72 40 82 27 56 +5 | 5.11 +1.14| 25 +22 Delta Cape 67 43 77 31 56 +3 | 8.60 +4.46| 24 +17 Girardeau | | Cardwell Dunklin 72 48 80 36 61 +6 | 3.90 -0.60| 36 +25 Clarkton Dunklin 71 46 80 33 59 +6 | 4.89 +0.63| 31 +23 Glennonville Dunklin 71 47 81 35 59 +5 | 4.51 +0.46| 32 +22 Charleston Mississippi 70 45 80 34 58 +5 | 5.02 +0.47| 27 +18 Portageville- | | Delta Center Pemiscot 70 49 80 38 60 +6 | 5.03 +0.89| 34 +24 Portageville- | | Lee Farm Pemiscot 71 48 80 35 60 +6 | 4.32 +0.19| 34 +25 Steele Pemiscot 72 49 82 37 61 +7 | 4.03 -0.42| 38 +28 -------------------------------------------------------------------------------- * Complete data not available for report ^Growing degree days are calculated by subtracting a 50 degree (Fahrenheit) base temperature from the average daily temperature. Thus, if the average temperature for the day is 75 degrees, then 25 growing degree days will have been accumulated. -------------------------------------------------------------------------------- Pat Guinan, Commercial Agriculture Program (573) 882-5908