Adults typically emerge over a two-month period (August to September); however, depending on weather, emergence can occur even up to harvest. drought delay adult emergence. The arid Southwest (West Texas, New Mexico, Arizona and California) has not yet had an established population of weevil develop. To deposit eggs in pecans, a female feeds through the shuck and shell to the kernel where she excavates a small cavity in the developing kernel. To determine the level of infestation and to best time spray applications, set up wire cone traps, pyramid traps and circle traps in the orchard to monitor weevil emergence. Beneficial nematodes for control of pecan weevils Pecan weevils are scientifically called as Curculio caryae. The pecan, Carya illinoensis Koch, is the most important native horticultural crop in the United States; however, the pecan industry is new compared to other orchard crops with commercial pecan production developing largely during the 20th century (Brison 1974). Under normal soil conditions, approximately 80 percent of adult weevils emerge between August 20 and September 10 (Fig. Drought conditions and clay soils delay emergence of adults by a month or more. The initial treatment should be made when the earliest maturing nuts of the early varieties are in the gel stage at the distal end of the nut. It’s impossible for a homeowner to spray insecticide over an entire tree but there are some strategies that might help control the weevils. COMMERCIAL PECAN INSECT CONTROL. As of 1999 , pecan weevil had been found in 131 Texas counties (Fig. The initial insecticide application should be effective for 5 days. The adult emergence period lasts for several weeks so time sprays to prevent oviposition rather than to protect a few nuts that will be lost to the small number of early emerging adults that feed during the water stage. Pecan weevils can be controlled by spraying liquid applications of carbaryl (commonly sold as Sevin) on the ground underneath trees out to the drip line, as well as up the trunks of pecan trees as far as you can reach, beginning in mid August and continuing every … This cell can be located between 4 to 12 inches below the surface, depending on the condition of the soil. However, soils hardened by. Several applications that blanket the presumed adult emergence period are made in an effort to kill every emerging weevil. What can be done to prevent this? During drought conditions in 1977 -78, almost 30 percent of the adult weevils emerged after an October 19 rain. They are approximately 3/5 of an inch long and are white with reddish heads. 8). She will avoid any pecans in which eggs already have been laid by other females. Pecan weevils are challenging to control because they spend much of their two- to three-year life cycle two feet underground, where treatments cannot reach, Sutherland said. The emergence of adult pecan weevils is directly related to the type of soil and soil. The adult female weevil is a beetle-like insect that emerges from the ground in early August each year. Bill Ree, Texas A&M AgriLife Extension, discusses pecan weevil damage and control, and also describes the quarantine process now in effect. but, under drought conditions, also will have delayed emergence from hard soils under the canopy but away from emitters. For article reprint information, please visit our Media Page. Hickory Shuckworm; Dimilin: 2F 12 fluid ounces per acre; Intrepid: 2F 6 fluid ounces per acre; Apta: 24 fluid ounces per acre ; Altacor: 3.2 fluid ounces per acre; Group 15; Group 18; Group 21A; Group 28; In early season, do not treat yellow aphids if they are the only insect problem. These adults remain in the soil for another year, which results in a 3-year life cycle. The remaining 10 percent delay pupation until the second year. These traps require little effort to put up and are relatively inexpensive. UG Cooperative xension ulletin 841 . I would like to subscribe to Science X Newsletter. These traps require little effort to put up and are relatively inexpensive. Adult weevils collected in the traps should be counted and removed with each inspection. To keep the material from … Control recommendations rely on broad spectrum chemical insecticides. This will greatly diminish the damage to your crop. Feeding activity of adult weevils, both males and females, before nuts enter the gel stage can cause nut drop. 7). several weeks or more, the initial insecticide application for pecan weevil is applied around August 20 to 22. The pecan weevil, Curculio caryae (Horn), is perhaps the most damaging insect in the majority of pecan-producing states in the U.S. A year later, about 90 percent of these larvae pupate during a 3-week period. Even in years where drought delays emergence and traps fail to collect adults, some pecan weevil adults will emerge through soil cracks before gel formation and this justifies the initial treatment. This emergence pattern is typical across the pecan belt. Pecan weevil adults (pictured at right) emerge from the soil starting in early August and continue emerging until early September. When fully grown, larvae reach a length of 3/5 inch (Fig. This eradication program requires a minimum 3-year period when no larval infestations appear in the harvests. Adults emerge from the soil where they have spent 2 or 3 years in soil cells located 4 to 12 inches beneath the soil surface. 2). After pupation, the adult pecan weevil remains in the soil for another year. Extension-made traps take the guess work out of pecan weevil control in Dougherty County. However, these traps are expensive, labor intensive and cannot be used with livestock unless the trap area is fenced. Female weevils bore through the shuck and shell of a nut to lay 5-7 eggs. David I. Shapiro-Ilan, Ted E. Cottrell, Clive Bock, Kim Mai, Debbie Boykin, Lenny Wells, William G. Hudson, and Russell F. Mizell, III. After the pecan kernels have been harvested and removed from the orchard, however, other insects can infest the kernels in storage. Schedule irrigation to ensure weevil emergence at the normal time, but allow time for soils to dry enough to allow pesticide sprayers access before emerging weevils can begin to lay eggs in nuts. Adult female pecan weevils do not begin to lay eggs until 5 days after emergence, so the earliest time to retreat will be 10 days after the initial application. To properly manage a successful pecan orchard, a well-developed plan should be implemented. Unlike treatment for the pecan nut casebearer, where infestations can vary from year to year by. For more details on pecan weevil control and the use of traps, see Oklahoma State University factsheets Biology and Control of Pecan Weevil in Oklahoma (bit.ly/pecan-weevil-control) and Monitoring Adult Weevil Populations in Pecan and Fruit Trees in Oklahoma (bit.ly/weevil-population). Integrated pest management (IPM) practices in pecan are designed to keep pecan weevil populations below economic levels. Also, the large brown adults are very secretive when they emerge and any eggs or larvae … Pecan Weevil: Wanted DEAD, Not Alive All About Discovery!TM New Mexico State University aces.nmsu.edu The College of Agricultural, Consumer and Environmental Sciences is an engine for economic and community development in New Mexico, improving the lives of New Mexicans through academic, research, and extension programs. A female will lay approximately 75 eggs in her life at a rate of 2.6 to 3.8 eggs per day. PEST PESTICIDE MOA AMOUNT PER ACRE REI/PHI (Hours or Days) TIMING AND REMARKS. Even though damage can occur from the time of adult emergence to shuck split, the key to weevil control is to prevent egg lay or oviposition. Trap efficiency is enhanced by keeping grass and weeds mowed around. Every year the pecans have a small hole with a white worm in them. They have reddish-brown heads and grow to 1/3 inch long. Other formulations of carbaryl also can be used. A close. Approximately 10% of larvae do not emerge at that time and can remain dormant an additional year. How to Treat Pecan Trees That Have Worms in the Nuts. For egg lay to be successful, nuts must be in the gel stage or later. $36.00–$270.00 If adult emergence traps are collecting adult weevils on or after the sixth day following the initial insecticide application, a second application is needed. Both the adult and larval stages of pecan weevil cause a serious damage to pecan nuts. This review is presented to describe the biology, life stages, crop injury, monitoring approaches, and primary control strategies currently used for pecan weevil in pecan.