Wheat stem sawfly is best known as a pest of wheat and has caused extensive losses to wheat in the northern Great Plains. If damage extends across the field, the whole field should be seeded with a resistant or non-susceptible crop. The first egg to hatch is cannibalistic on any other eggs present in the same stem. COVID-19 case updates (including the map and dashboard) will not be available on December 25, 26, 28 and January 1. Generally it appears that less soil disturbance will result in more adult emergence. A few more growers and wheat acres in Nebraska became familiar with wheat stem sawfly damage during this past growing season. The second generation of parasites appear about mid-August. Help us improve, First Nations, Métis and Northern Citizens, Agriculture, Natural Resources and Industry, COVID-19 Information for Businesses and Workers, Environmental Protection and Sustainability, First Nations, Métis, and Northern Community Businesses, Housing Development, Construction and Property Management, Cabinet, Ministries, Agencies and Other Governments, Educational Institutions and Child Care Facility Administration, Health Care Administration and Provider Resources, Legislation, Maps and Authenticating Notarized Documents, Egg-laying continues and larval feeding commences, 45 Thatcher Drive East, Moose Jaw, SK, Canada, S6J 1L8. Although the sawfly may lay eggs in other cereals, including barley, oat, and rye, larvae rarely mature in barley and rye and do not survive in oat. The most preferred hosts are spring and durum wheat, although rye, triticale and even barley can be affected. Soil type may also influence the elongation of solid stems. Sawfly damage (SFLY DMG) Description. The larvae overwinter in the stubs, slightly below soil level, before pupating in early spring. What made this season different was that far more acres were impacted in Kimball, Cheyenne, Garden, and Deuel Counties than ever have been in the past 10 years. Learn more about us or about our partners. Losses in yield were compounded by additional operating costs (harvesting in one direction) resulting in an average loss of $10/acre. Adults are approximately eight to 13 millimetres (mm) (5/16 -1/2 Inch) in length and are characteristically inactive, often seen resting on wheat stems with their head directed downward (Fig. Shallow tillage after harvest lifts the crowns and loosens the soil around them. Employment |
Case numbers are updated daily. Many producers consider the wheat stem sawfly to be a problem only in field margins. Find a government service and access your Saskatchewan Account. Heavy winds, rain and other factors contribute to increased lodging that can be even more apparent in thin stands. The wheat stem sawfly is the most destructive pest in wheat production in Montana. Durum wheats are semi-solid and are rarely attacked by the sawfly. It may take several years for the parasite populations to increase to effective levels. The wheat stem sawfly map is based on cut stem counts conducted in the fall of 2019 and the damage ratings are based on 90 fields in 21 municipalities. A swathing operation may reduce grain losses, but operational costs would increase by $7/acre. If cool, wet weather occurs during emergence, the period of emergence is extended. The first generation appears in June and July when adult sawflies are present. They tend to remain near the area where they emerge because they are weak fliers. They are not strong fliers and usually only fly until they find the nearest wheat field or other suitable host grasses. Sawflies lack the conspicuous constriction between thorax and abdomen that is characteristic of most other members of this family. If wheat is to be grown as part of a current rotation, solid stem wheat varieties should be grown as they are considered to be more resistant to sawfly damage. I received several phone calls in July from wheat growers that had decent stands of wheat at flowering only to find fallen tillers the week of harvest – the hallmark of wheat stem sawfly damage. The most effective way to reduce damage from the wheat stem sawfly is through the incorporation of resistant cultivars and/or crops. However, when sawflies are abundant, females may move past the trap crop and into the wheat to oviposit, resulting in significant damage. They produce a clear protective covering that protects them from excess moisture and moisture loss. Revised 10/14. Sawfly feeding also can reduce the protein content of the grain. The wheat stem sawfly, Cephus cinctus (Hymenoptera: Cephidae), is an important pest of wheat and other grain crops in the northern Great Plains. In the early 1980s, however, it emerged as a significant pest of winter wheat as well. There is only one generation per year. Although the adult female lays eggs in the plant stem, she does not feed on the plant. The most visible wheat stem sawfly damage is stem breakage or lodging just prior to harvest (Figure 4). As the plant starts to senesce (ripen), allowing sunlight to filter through the stem, the larvae respond by moving toward the bottom of the stem and turn around. Economic loss due to the wheat stem sawfly may be a reduction in yield and/or grade as a result of larval feeding within the stem. Tractor farming increased the rel… Grass sawfly larvae hatch and feed on the lower leaf blade in early May. Adults will typically emerge in late-June and the first week of July. Yield loss of five to ten percent due to unrecoverable wheat heads are common. The European wheat stem sawfly, Cephus pygmeus (Linnaeus, 1767) and the black grain stem sawfly, Trachelus tabidus (Fabricius, 1775) are important and common pests in wheat growing areas of Turkey. If swathing is not economically or operationally feasible, combine the field as soon as grain moisture is low enough to bin the seed. Translations are made available to increase access to Government of Saskatchewan content for populations whose first language is not English. These translations are identified by a yellow box in the right or left rail that resembles the link below. Even if a field is heavily infested, most wheat heads can be recovered if producers swath the crop early to create a more harvestable windrow. Though the soil erosion benefits of planting in narrow strips may be reduced, larger fields are still a viable option if erosion is addressed by no-till practices. Stem strength and stand density may also be factors in affecting crop loss. Other females may lay eggs in the same stem, but only one larva will survive per plant. The average crop value during the study was $41.50/acre, and average yield was only 14 bushels per acre. Learn more about COVID-19 in Saskatchewan. Wheat stem sawfly was slow to adapt to cereals but achieved pest status in the 1910s and 20s. Prevention. The wheat stem sawfly is an insect that girdles the stem of wheat plants and causes the plant to lodge just prior to harvest. Attempts to harvest the fallen plants often result in considerable equipment damage and increased fuel costs. grains, the host range of the wheat stem sawfly expanded and wheat was found to be a viable and easily accessible host. Within the stem, the larvae feed upward, boring through the nodes for a month or longer. As it grows, the larvae will climb and continue to feed on stems and leaves. Spring wheat was the primary cereal grain impacted by this pest but it has subsequently infested and severely affected winter wheat as well. ©2021, Colorado State University Extension, Fort Collins, Colorado 80523 USA. Monitor the field again in late-July. While the crop is still green, infested stems may appear with regions of mottled discolouration. Since then, sawfly infestations in winter wheat have spread from North Dakota and Montana into southeastern Wyoming, the Nebraska Panhandle, and, most recently, northeastern Colorado. In Montana, winter wheat, the most common wheat class, is severely affected. If sawflies are present, harvesting the perimeter of the crop as green feed may be an option, as this practice will likely destroy the larvae. Warm, sunny, calm weather following spring rains will result in wider dispersal of the insect within a field or to adjacent fields. The name sawfly is used because of the saw-like ovipositor (organ) used by the female sawflies to cut into the plant tissue to lay eggs. The Braconid wasps, Bracon cephi, and a close relative, Bracon lissogaster, attack the larvae of the wheat stem sawfly resulting in significant reductions of sawfly populations. Estimates suggest a five to 15 per cent decrease in total seed weight. One research study indicated that larval mortality was about 28 per cent in hollow stems and about 67 per cent in solid stems. Intense tillage that buries stubble also reduces sawfly survival, but to a lesser degree. We need your feedback to improve saskatchewan.ca. They take about five to eight days to hatch. Sawfly damage, which leaves stalks laying flat at or near harvest, is becoming more prevalent, he said. The wheat stem sawfly was not a significant pest for a number of years. Tillage has been shown to have some effect in reducing sawfly populations. Marc Arnusch’s phone has been ringing with calls from wheat growers preparing to plant after a year wrought with sawfly damage. There are naturally occurring enemies of the wheat stem sawfly. Its history in Canada dates from 1895 when it first damaged wheat near Moose Jaw, Saskatchewan, and Souris, Manitoba. Note that while field #2 (found in the northern panhandle) had a 90% wheat stem sawfly infestation (i.e., frass found in 90 of 100 sampled tillers), all of the sawfly larvae in the sampled tillers were dead and a majority of the sawfly mortality in that field could be attributed to parasitism (a large percentage of infested tillers contained a parasitoid pupa). Although the sawfly may lay eggs in other cereals, including barley, oat, and rye, larvae rarely mature in barley and rye and do not survive in oat. It does not attack corn or broad leaf crops. Damage to winter wheat was first reported in Colorado in 2010, from areas along Colorado Highway 14 in Weld County. In each field, the number of wheat stem sawfly cut and the number of uncut stems are determined in a one meter of stubble in four locations. The wheat stem sawfly is a major problem in the Mediterranean Basin. There are no insecticides registered for wheat stem sawfly and research trials have not shown any insecticides to be cost effective. Journal of Economic Entomology, 87(5):1373-1376 Painter RH, 1953. Barley is not normally a host for the sawfly. It was first noticed in Canada in late 1800’s. Select a resistant variety such as AC Lillian. Although past reports suggested durum wheat varieties were rarely attacked, some durum varieties appear to be as susceptible as some spring wheat varieties. In addition, physiological damage caused by feeding activity results in yield losses of ten to twenty percent in infested heads that are harvested. Agriculture and Agri-Food Canada researchers have investigated a number of aspects relating to wheat stem sawfly population dynamics and host plant phenology, as well as management options, including the use of trap crops, and blending resistant and susceptible cultivars together. Contact your local county Extension office through our County Office List. Overall, the negative effects of burning far outweigh any benefits. Non-Discrimination Statement |
Spring tillage only provides about 25% sawfly mortality. Other traits should be similar between the varieties grown such as maturity and height in order to reduce variation when harvesting. The related European wheat stem sawfly occurs in Europe, Asia, Africa, Canada and the USA. Delayed planting of wheat may be of some benefit to reduce sawfly damage, but yield and quality may also be affected. Ideally, the strategy should be a community commitment since isolated attempts to manage sawfly populations will always be affected by populations in neighbouring fields. The upper stem often breaks at this weakened notch just prior to harvest, and the remaining stem containing the overwintering chamber is referred to as the ‘stub’ (Figure 3). The wheat stem sawfly has traditionally infested spring wheat, but over the last few decades the damage is becoming increasingly common in winter wheat. The wheat stem sawfly, long considered a severe pest of wheat in Montana and North Dakota, was found infesting wheat along Highway 14 in Weld County in 2010 and again in 2011. The insect is found across much of western North America though damage to wheat occurs primarily in Montana, the Dakotas, western Nebraska, eastern Wyoming, and the Canadian Prairie Provinces. This study is designed to develop, implement and evaluate management tactics against the wheat stem sawfly. An adult sawfly is shiny black with three yellow bands around the abdomen. However, tillage operations can contribute to soil erosion and, therefore, producers should consider this option carefully, especially in lighter soil. The common name comes from the saw-like appearance of the ovipositor, which the females use to cut into the plants where they lay their eggs. CSU Extension programs are available to all without discrimination. Eggs are approximately one mm long, milky white and crescent-shaped. This damage is very apparent at harvest time and will be easily observed by the combine operator. The wheat stem sawfly (Cephus cinctus Norton) is brown with yellow legs and approximately 1/2 inch long. It also feeds in several hollow-stemmed non-cultivated grasses, including quackgrass, smooth brome and various wheatgrasses. However, each of these have specific agronomic costs. Most obvious signs of crop damage are cleanly broken stems caused by larval tunnelling and construction of pupation chambers. If the kernels appear shrivelled or distorted as a result of sawfly feeding, the Canadian Grain Commission limits damage to No. Damage to winter wheat has yet to be observed in a few counties. Annual losses are estimated at $25 - 30 million. The average crop value for the solid stemmed cultivar, AC Abbey, was $51.60 per acre. Both parasites mentioned can have two generations annually. Darkened areas on the stem, just beneath the node, indicate larval infestation. Feeding by wheat stem sawfly larvae reduces the plant’s vascular efficiency and results in fewer kernels per head and lower kernel weight. 1). With head now upwards, the larvae cut a groove around the entire inside of the stem generally less than 25 mm (one inch) above the ground. Tillage has been shown to reduce wheat stem sawfly survival. While there are no in-season control measures, planting solid stem varieties this fall may lessen damage due to lodging in next year's crop. Spring tillage operations, however, do not appear to have as negative effects on the sawfly populations but do help reduce populations. In areas where the sawfly is a recent arrival, wheat breeding programs are beginning to focus on incorporation of the solid stem characteristic into adapted varieties, using both conventional selection and linked DNA markers. These sawfly species continue to be a threat to wheat production in the southeast Anatolia Region of the country. The cut weakens the stem so it falls over easily making it difficult to harvest, resulting in yield loss. Other factors to consider if one is using resistant varieties alone or mixed (i.e. Planting wheat in larger blocks as opposed to narrow strips is another cultural practice that may reduce sawfly damage potential. This results in an overall reduction in the number of seeds per head and a corresponding yield decrease ranging from five to 15 per cent. The larvae produce a long, thin, brown transparent cocoon below the cut in the stem. Throughout most of the 20th century, winter wheat in the Great Plains escaped wheat stem sawfly damage as the wheat stem sawfly was not synchronized with winter wheat phenology (Lou et al. If mixing varieties, the same wheat class should be used to prevent downgrading. Providing trusted, practical education to help you solve problems, develop skills and build a better future. If seed source is an issue, spread out resistant variety as much as possible by seeding borders (trap cropping) of fields to the resistant variety. Using solid-stemmed cultivars and cultural controls are currently the most effective alternatives. Find services and information for doing business in Saskatchewan. Find how the Government of Saskatchewan governs and serves the province. This type of damage can reduce yield on infested stems by up to 20 percent. Privacy Statement |
Eggs are laid on or near the sawfly larvae. There are no established economic thresholds for wheat stem sawfly, however, producers are recommended to implement management strategies if 10 to 15 per cent of the stems were cut the previous year. Adults emerge in late May or early June and are generally active when winds are calm and field temperatures are above 50° F. The adult wheat stem sawfly (Figure 1) is about ¾ of an inch long with smoky-brown wings. Colorado State University, U.S. Department of Agriculture, and Colorado counties cooperating. In laboratory tests, sawfly larvae did not survive temperatures below minus 22 degrees C, but larvae are more buffered from temperature extremes in their location at or below the soil surface. A stem filled with a sawdust-like substance indicates feeding activity. I received several phone calls in July from wheat growers that had decent stands of wheat at flowering only to find fallen tillers the week of harvest – the hallmark of wheat stem sawfly damage. 1998 By the mid-1980s, ). Our physical location is 1311 College Ave, Fort Collins, CO. Having website issues? Larvae are cream coloured, wrinkled and are more strongly S-shaped (Fig. The wheat stem sawfly is a major problem in the Mediterranean Basin. A healthy adult female may lay up to 50 eggs, usually only one egg per stem. Pupae will not be formed until the following May. Sawfly larvae are always found within the stem and will assume an S-shaped position when taken out of the stem. If you have any questions about Google™ Translate, please visit: Google™ Translate FAQs. Equal Opportunity |
Stem and head clipping often occur before leaf feeding is complete and/or the grain reaches physiological maturity. Review all public health measures. This requires judgment as swathing too early can result in low-test weights, reduced yields and downgrading. Within this geographical region, the areas subjected to greatest attack are southern Alberta and Saskatchewan, southwestern Manitoba, eastern and northern Montana, North Dakota, northern South Dakota, and … Sawfly damage can lead to stem breakage or lodging prior to harvest. In minimum till systems, the emphasis should be on host plant resistance, delayed planting of susceptible varieties, and rotations that include non-susceptible cr… It does not attack corn or broad leaf crops. If several stems split in late-July contain a larva (i.e.. four to six larvae per 10 stems split), consider swathing the crop. In addition to losses from lodging, sawfly larvae cause physiological damage of 10 to 20 percent to the inf… If damage in the previous year is confined to the field edges and has reached 10-15 per cent stems cut, resistant varieties could be seeded around the perimeter of the field as a "trap" or "barrier crop," with a high performing conventional variety in middle of the field. Wheat stem sawfly can cause a lot of damage to a wheat yield, and there aren’t a lot of options to control it. Natural, indigenous hosts include some native grass species (mostly wheatgrasses – genus Agropyron), generally with larger stems. Since that time, it has been found infesting winter wheat as far south as Baca County. Shallow, fall tillage can result in 90% sawfly mortality. Different insects cause the two damages. Burning infested stubble has been considered as a possible strategy. Wheat lines having solid or partially solid stems are much less susceptible to attack. Sawfly damage, which leaves stalks laying flat at or near harvest, is becoming more prevalent, he said. 6). To some degree, the adoption of conservation tillage practices that leave stubble containing sawfly larvae intact may also favour increased wheat stem sawfly populations. The program at Colorado State University also is initiating long term research into novel methods for making the wheat plant less attractive to the sawfly. No-till has been linked to many of the recent wheat stem sawfly problems in the region. Conversely, a high percentage of stems could already be toppled over if the swathing operation is performed too late. The primary hosts for the wheat stem sawfly are cultivated cereal crops. Solid stem varieties of wheat have been shown to be effective in reducing damage caused by the wheat stem sawfly. At maturity, the larvae can reach a length of about 13 mm (1/2 in). In the absence of severe sawfly pressure, producers tended to choose wheat varieties that offered attributes such as increased yield, protein and disease resistance rather than sawfly resistance. The Braconid wasps, Bracon cephi, and a close relative, Bracon lissogaster, attack the larvae of the wheat stem sawfly resulting in significant reductions of sawfly populations. There are naturally occurring enemies of the wheat stem sawfly. Some strategies are more practical and useful than others. Winter wheat is not normally the preferred host in Canada, but there have been cases where it has been infested as severely as spring wheat. Adults emerge in late May or early June and are generally active when winds are calm and field temperatures are above 50° F. Several parasitic wasps attack wheat stem sawfly but the presence and effectiveness of natural enemies in Colorado has not been determined.