0000092691 00000 n Choose blocks that have known history of pecan weevil infestations for monitoring. The larvae hatch from the eggs and feed inside the nut, destroying the kernel (Fig. The pecan weevil will also breed in hickory nuts. The female’s snout is as long as its body; the male’s snout is somewhat shorter (Fig. i��qO�sxٱ�|S�F�U-a�]G0�����J���1��9̋ӳ�>c�Y�+?��Q}���f����K�1�O�E��=4���c�n�d�w�a�S�S���{��0i�e/��u�v�Q��0��w�!^g8�A}3��/M������Q��* ������zS&�[,��ϙp��?�m �α�-V�픻�ٶ�A����o����Nو���(�+\@[͍N�ql~��PO"��(�є��ѯ_�T^�:��+���-K�E�d������nt���de��ѷ�`��?Ǘ!�L�K�3��u���e (�G0Ր�����T���5é�3��� |]�j����3"�C��SEz�VR(ؖ���. But it does cause the nuts to be inedible. 0000001298 00000 n From the Southwest Yard & Garden series. Common Name: Pecan weevil 0000003833 00000 n Descriptions of Larvae Pecan Weevil Larvae (Curculio caryae) These robust, dirty white, somewhat C-shaped larvae are up to 5/8 inch in length when fully grown. Early damage causes these nuts to fall to the ground prior to maturity. Scientific Name: Curculio caryae (Horn) Larger chestnut weevil grubs chew an exit hole in the side of the nut and drop to the ground usually before the nuts fall. Because the larvae, pupae and adults are covered with 4 to 12 inches of soil and pesticides cannot reach larvae inside the nuts, management of these life stages is not practical. This weevil cannot fly, so will be found close to the areas it infests. 0000001716 00000 n 0000001144 00000 n 0000003169 00000 n In 1986, W. L. Tedders recov- ered H. bacteriophora Poinar Georgia strain from dead, reddish-colored weevil larvae found in a pecan orchard at Byron, Geor- As of 1999, pecan weevil had been found in 131 Texas counties (Fig. Ma-ture larvae may be about 1/3 to a little over 1/2 inch long. Later in the season when pecan nuts are present, moths deposit eggs singly on the nuts. Oklahoma Pecan Growers Assoc. Ovipositional damage. trailer << /Size 52 /Info 26 0 R /Root 29 0 R /Prev 280064 /ID[<8b5080b40d262f6b3a54b5e468d931bc>] >> startxref 0 %%EOF 29 0 obj << /Type /Catalog /Pages 25 0 R /Metadata 27 0 R /PageLabels 24 0 R >> endobj 50 0 obj << /S 62 /L 129 /Filter /FlateDecode /Length 51 0 R >> stream Pecan Weevil, Curculio caryae Hosts: The only economic host is the pecan where feeding and breeding take place in the developing nuts. 1984. 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Attraction of the pecan weevil to the synthetic boll weevil pheromone. Pecan weevil is considered the most significant insect pest of pecan producers. Steinernema carpocapsae (Weiser) strain A11, S. feltiae (Filipjev) strain SN, and Heterorhabditis bacteriophora Poinar strains HP88 and Georgia were tested for their efficacy as biological control agents of the pecan weevil, Curculio caryae (Horn), in pecan orchard soil-profile containers under greenhouse conditions. Click for a hub of Extension resources related to the current COVID-19 situation. Circle traps are useful for weevil monitoring, providing good indications of weevil presence and abundance within an orchard. 0000032111 00000 n Pecan weevil: suppression of larvae with the fungi Metarrhizium anisopliae and Beauveria bassiana and the nematode Neoaplectana dutkyi. They are found in the nuts during late summer and early fall and can be found in the soil beneath infested trees during the rest of the year. Once the larvae hatch, they feed on the kernel for about 35 days. Early damage causes these nuts to fall to the ground prior to maturity. Literature: Crocker et al. Beneficial nematodes for control of pecan weevils. Weevil larvae feeding in a pecan nut. %PDF-1.3 %���� If not contained, the pest could affect the state’s pecan industry’s economic impact. (A) Eggs, circled; (B) 4th instar larva; (C) Pupa inside earthen cell and (D) Adult female on pecan. The pecan weevil has a predominantly 2-year life cycle co-inciding with masting by its Carya host. Lesser weevil grubs eat through the shells after the nuts drop. Its larvae (soft, white grubs without legs) and white pupae are similar to those of the rice and maize weevil. 0000002511 00000 n Occasionally, a small number of pecan weevil larvae will undergo a two-year diapause which extends the life cycle an additional year. No other insects develop in pecan kernels in the field, although larvae of several pests, such as the Indianmeal moth, Plodia interpunctella (Hübner) (Lepidoptera: Pyralidae), can infest stored pecans. The larvae are cream colored grubs with reddish heads. The pecan weevil, Curculio caryae (Horn), is a dangerous nut pest of pecan found throughout the southern United States and portions of Texas. Description: Adult pecan weevil adults are 3/8 inch long, brownish beetles with snouts as long as the body. Later damage caused by larvae feeding on the developing kernels makes the nuts worthless. Pecan weevil pupa. 0000004055 00000 n 28 0 obj << /Linearized 1 /O 30 /H [ 920 224 ] /L 280752 /E 108681 /N 5 /T 280074 >> endobj xref 28 24 0000000016 00000 n Weevil larvae feeding in a pecan nut. The pecan weevil causes two types of damage. Life cycle The adult PW typically emerges from the soil as early as July 25, frequently two to three days after a heavy rain. The adult is a brownish weevil, about 3/8 inch long. Learn how to identify damage to pecans caused by the pecan weevil. The first type is when the adult weevils puncture the nuts in early August, causing the nuts to fall after two or three days. Workers at an Otero County pecan cleaning plant noticed pecans with round holes about the diameter of a BB pellet, which are the pecan weevil's emergence holes. 0000006107 00000 n For more information on pecan weevil control and other research-based orchard management practices, consult OSU Extension fact sheets, available online and through all county Extension offices . Pecan weevil adults damage pecan each year just before and after initiation of kernel development by feeding directly on the nuts and by oviposition (Boethel and Eikenbary 1979). The larvae emerge from the nuts about 42 days after the eggs are deposited. First, they feed on the young nuts in late summer, causing some to drop early still in their husks and never complete development. Larvae and pupae become common in flower beds and gardens in which acorns have fallen. Before shell hardening, treat if high numbers of weevils are seen or if nut drop caused by weevil feeding is high. Larval emergence holes in pecan nut shucks and shells begin to appear in late September and continue as long as larvae are alive. First, they feed on the young nuts in late summer, causing some to drop early still in their husks and never complete development. 1). Abstract Neoaplectana dutkyi and 2 species of fungi were evaluated in laboratory and field tests as pathogens of Curcubio caryae larvae. To control the weevil, it is recommended to target with … The larvae leave the nut and burrow into the soil, remaining there for two to three years before emerging as adults to commence another cycle. Koch] (Fagales: Juglandaceae) is an economically important North American nut crop ().The pecan weevil, Curculio caryae (Horn) (Coleoptera: Curculionidae), is a key pecan pest affecting orchard nutmeat yield and quality throughout the Southeastern United States, and portions of Texas and Oklahoma (Payne and Dutcher 1985). 1). Four life stages of the pecan weevil. The majority of adults emerge from the soil during August and the first week of September. early egg-laying period, from early August to mid-September. It has also been observed to infest one Juglans species, the Persian walnut, Juglans regia. Holloway et al. Pecan weevil larvae (4 th instar), collected from infested nuts on the USDA-ARS Research Station (Byron, Ga.), were stored in sterile (autoclaved) soil at 25° C. for two weeks, at which time diseased larvae were removed. The larvae emerge from the nuts about 42 days after the eggs are deposited. The larvae are cream colored grubs with reddish heads. The female’s snout is as long as its body; while the male’s snout is somewhat shorter. ... Larvae on pecan feed in phylloxera galls in spring. Larvae or grubs are legless, creamy white and have reddish-brown heads which grow to 3/5 inch long. H��W˒۸��+�$Sj6�����Ljf�RYx��(HB�M� d��o$�{/ ����$r���s���߬7�8��W�H�����]��'+�"�J�yY=~�%k-=�2�������`Wi��i�6��.�9��?�V��oJ��.��cų�﮲:M�~� )e��C�p�K� nd �����\���Q�G�:���::!��CjRV�MR�)�g�[_� �#t��خ�'mG��Ө���������'�������BMӤ�gT�M�n}�����hsT�z���Y������i� p�R�H���i�N��&Γ*:�P�*�*��^�I����d��N螽�u�EC�&EdG6�G�J���, �m�x��q����3�8����:�~���,�み�zT;�q���d��I]���`Hpg(a�=ؙ��g�4��Zc�oRF>�OZՏ.xSD�vS�����*��u�a2_ô���ǁ��#��o��I�Q��Y Google Scholar. Traps can be obtained for around $18 each from Pecan Ag Equipment in Bristow, Oklahoma (1-918-367-5529). 4). Abstract Neoaplectana dutkyi and 2 species of fungi were evaluated in laboratory and field tests as pathogens of Curcubio caryae larvae. Each female weevil can oviposit 30 to 54 eggs; therefore, one weevil could affect as many as 15 to 27 or as few as 7 to 13 pecans, assuming there are two to four larvae per nut, respectively. Hosts. Pecan Weevil, Curculio caryae Hosts: The only economic host is the pecan where feeding and breeding take place in the developing nuts. “A female weevil can produce 30-54 eggs, so several nuts can be affected from each egg hatch,” Mulder said. In late fall and early winter, about 42 days after eggs are laid, full-grown larvae chew a 1/8 diameter hole in the shell and drop to the ground. Adults of pecan weevil generally emerge from soil in late July to August and move in the tree canopy by either crawling on the trunk or directly flying. Pecan Weevil, Curculio caryae ... Eggs hatch in 5 to 7 days and the larvae feed for 2 to 3 weeks before leaving the nut. 11). Pecan South 2(5): 194–196. Once the larvae hatch, they feed on the kernel for about 35 days. Traps can be obtained for around $18 each from Pecan Ag Equipment in Bristow, Oklahoma (1-918-367-5529). are susceptible to this indigenous pest ( Ring et al., 1991 ). 11). Descriptions of Larvae Pecan Weevil Larvae (Curculio caryae) These robust, dirty white, somewhat C-shaped larvae are up to 5/8 inch in length when fully grown. The adults can live up to 8 weeks, during which time the female can lay up to 200 eggs. Pecan weevil is considered the most significant insect pest of pecan producers. Adult weevils become active in August and early September. Larvae or grubs are legless, creamy white and have reddish-brown heads which grow to 3/5 inch long. The head is yellow to brown. Figure 7. But it does cause the nuts to be inedible. The arid Southwest (West Texas, New Mexico, Arizona and California) has not yet had an established population of weevil develop. The pecan weevil, Curculio caryae is a serious economic pest of pecans (Caryae illinoensis).In late summer, the weevil attacks maturing nuts and damages them when making feeding and/or oviposition punctures. Pecan weevil larvae can be found inside infested pecan nuts before and after nuts are removed or fall from the tree. ... Larvae on pecan feed in phylloxera galls in spring. (Photo by Bill Ree) During my time as the pecan IPM specialist for Texas A&M AgriLife Extension, I have written several articles for Pecan South on pecan weevil management, but for this month instead of a management focus, I would like to address the potential spread of pecan weevil to new areas. If not contained, the pest could affect the state’s pecan industry’s economic impact. INTRODUCTION THE PECAN weevil, Curculio caryae (Horn), attacks green maturing nuts in late summer and damages them by making feeding and oviposition punctures. Pecan weevils are scientifically called as Curculio caryae. • Pecan weevil larvae are legless, plump, and creamy white, and their bodies have multiple segments. Pecan Weevil Alert Pecan weevil management decision-making is already upon us. As of 1999, pecan weevil had been found in 131 Texas counties (Fig. Learn how to identify damage to pecans caused by the pecan weevil. When fully grown, larvae reach a length of 3/5 inch (Fig. The objective in a pecan weevil integrated pest management (IPM) program is to prevent female weevils from laying eggs in nuts. Adult and larval acorn weevils are similar in appearance to pecan weevils and often occur around homes surrounded by oak trees. Later in the season when pecan nuts are present, moths deposit eggs singly on the nuts. The larvae leave the nut and burrow into the soil, remaining there for two to three years before emerging as adults to commence another cycle. Note that many pecan growing areas are facing dry conditions, and this may result in drought-delayed emergence well beyond the normal emergence time for this pest, particularly in … In 1986, W. L. Tedders recov- ered H. bacteriophora Poinar Georgia strain from dead, reddish-colored weevil larvae found in a pecan orchard at Byron, Geor- 4). (year 3). Please keep in mind that the original opening on the trap top was designed for the boll weevil, which is a much smaller weevil, so be sure to check that the opening is somewhat enlarged for the larger pecan weevil. The pecan weevil, Curculio caryae (Horn), is perhaps the most damaging insect in the majority of pecan-producing states in the U.S. Feeding during the water stage prior to shell hardening causes damaged nuts to drop. from Ontario, Canada (Foott and Timmins 1984). Order: Coleoptera. The adult is a brownish weevil, about 3/8 inch long. Although feeding The entire life cycle takes 2 or 3 years. Google Scholar. Please keep in mind that the original opening on the trap top was designed for the boll weevil, which is a much smaller weevil, so be sure to check that the opening is somewhat enlarged for the larger pecan weevil. 79 tory conditions and reported 80, 86, and 75% larval mortality, respectively, after 28-35 days. Adults cause two types of nut damage, depending on the stage of nut development during attack. early egg-laying period, from early August to mid-September. Workers at an Otero County pecan cleaning plant noticed pecans with round holes about the diameter of a BB pellet, which are the pecan weevil's emergence holes. The head is yellow to brown. Pecan weevil (Curculio caryae) Figure 3 Adult pecan weevil on a mature nut. They are found in the nuts during late summer and early fall and can be found in the soil beneath infested trees during the rest of the year. Description The adult is a brownish weevil about 3/8 inch long. Larvae are fat, creamy-white, legless, C-shaped grubs, 9-15 mm long, with reddish-brown heads. Descriptions of Larvae Pecan Weevil Larvae (Curculio caryae) These robust, dirty white, somewhat C-shaped larvae are up to 5/8 inch in length when fully grown. 1987; Holloway 1980. Pecan Weevil, Curculio caryae ... Eggs hatch in 5 to 7 days and the larvae feed for 2 to 3 weeks before leaving the nut. To control the weevil, it is recommended to target with … The use of polyvinyl acetate as a barrier to the pecan weevil larvae. One to four larvae develop inside each nut and destroy the entire kernel. Proc. The pecan weevil burrows into the nut before the shell hardens and lays eggs, then worms hatch from the eggs and devour the nut. Pecan weevils are scientifically called as Curculio caryae. Larvae are fat, creamy-white, legless, C-shaped grubs, 9-15 mm long, with reddish-brown heads. Each female weevil can oviposit 30 to 54 eggs; therefore, one weevil could affect as many as 15 to 27 or as few as 7 to 13 pecans, assuming there are two to four larvae per nut, respectively. Choose blocks that have known history of pecan weevil infestations for monitoring. Pecan Weevil. 0000000827 00000 n The larvae are cream colored grubs with reddish heads. Grubs overwinter in earthen cells in the ground. The pecan weevil is a pest to start controlling in August and September to prevent discovering problems later this year. Pecan Weevil in Oklahoma Figure 1. One prime example is the so-called plum curculio (Conotrachelus nenuphar), which is a serious pest on a wide variety of stone fruits. Their presence does not stop development of the pecan so they may make it into the harvest. After eggs hatch, young legless larvae feed for about 30-35 days inside pecans. Larval stages develop in more developed nuts (dough stage), destroying the kernels. For more information on pecan weevil control and other research-based orchard management practices, consult OSU Extension fact sheets, available online and through all county Extension offices . Mated females chew a hole in the pecan shell and deposit eggs inside. One prime example is the so-called plum curculio (Conotrachelus nenuphar), which is a serious pest on a wide variety of stone fruits. Both the adult and larval stages of pecan weevil cause a serious damage to pecan nuts. Acorns of live oaks in urban areas of North Central Texas are sometimes 100 percent infested by larvae of acorn weevils. Later damage caused by larvae feeding on the developing kernels makes the nuts worthless.