Field Key to Larvae in Pecans 1 |
Previous | 1 of 4 | Next |
|
small (250x250 max)
medium (500x500 max)
Large
Extra Large
large ( > 500x500)
Full Resolution
All (PDF)
|
This page
All
|
Division of Agricultural Sciences and Natural Resources • Oklahoma State University F-7163 Oklahoma Cooperative Extension Fact Sheets are also available on our website at: http://www.osuextra.com Field Key to Larvae in Pecans Phil Mulder Extension Entomologist Don C. Arnold Survey Entomologist This key is designed to serve as a guide to identification of the more typical larvae of the common insect species found in pecans and on pecan trees in Oklahoma. The identifying characters used are based upon those found on full-grown or nearly full-grown larvae and may not necessarily occur on newly hatched larvae. If the larva in question does not fit the proper description furnished, recheck the specimen with the key. If it continues to key out improperly or is not one of the species listed, and proper identification is desired, place the larva in a small bottle containing 70% alcohol and mail to: Department of Entomology and Plant Pathology, Oklahoma State University, Stillwater, Oklahoma 74078. Please do not send specimens for identification unless they are causing or suspected of causing damage to the crop. Please include information as to the type and amount of damage noted as well as the date and community where the larva was collected. This information will assist in getting a more accurate and rapid reply to your questions. Some insects found on pecans cannot be identified with this key. This would include adult insects, closely related organisms, and such insects as aphids and phylloxera, which do not have a larval stage. Be sure you have insect larvae before attempting to use this key. All insect larvae normally found on pecans are included in this key. This key should be used primarily for larvae on pecans, but should be moderately accurate for larvae on walnut trees, also. Keys for other crops are available and can be obtained from the local county Extension office. Survey Methods Most pecan insects should be reported as the number per nut cluster or per tree. In the early season, the pecan nut casebearer should be reported as the number of eggs or larvae per 100 clusters. The color of the eggs should also be reported. After the nuts set, the number of damaged nuts per 100 clusters should be reported. Depending on the size of the grove, at least 50 clusters should be inspected. The hickory shuckworm should be reported as the number of damaged nuts per 100 nuts to give the percentage infestation. Pecan weevil surveys are made by jarring the tree and counting the weevils that fall. This is much easier if a light colored cloth or plastic sheet is placed under the tree. This should be reported as the number per tree or limb. Also, the size of the tree should be reported. Larvae in the nuts should be reported as the percentage of nuts infested. Adult emer-gence can be checked with screen wire cages placed under infested trees about mid-summer. Leaf-feeding larvae should be reported as light if very small numbers are present and little damage has occurred. If noticeable damage has occurred, it should be reported as the percentage of defoliation. The fall webworm can be reported as the number and size of webs per tree and the percentage of trees infested in the immediate area. 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 head is yellow to brown. 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. Pecan Nut Casebearer (Acrobasis nuxovrella) The body color is pale borwnish-yellow to light gray brown. The head is reddish-brown with deeper brown spots. They are up to 5/8 inch in length when mature. Over-wintering larvae feed on the buds and bore into young shoots in spring. The first generation larvae attack the young nuts in late spring, often webbing them together. Second generation larvae at-tack larger nuts in early summer. A third generation occurs later, but does little damage. Walnut Caterpillar (Datana integerrima) Young larvae are reddish with narrow yellowish or gray-ish lines, which extend the entire length of the body. Mature larvae are black with only two grayish lines on the back and two on the sides. Many soft, fine, long, grayish hairs cover the entire body. They may be up to 1 1/2 inches in length. They feed on leaves, in groups, and do not form webs on the leaves. There are two generations per year. Fall Webworm (Hyphantria cunea) These larvae vary from light buff to near black. They are covered with long light-colored hairs. They may be up to 1 1/4 inches long when mature. They make large webs on the trees and live and feed in them. There are two generations per year. Some authorities recognize two species; H. cunea and
Object Description
Okla State Agency |
Oklahoma Cooperative Extension Service |
Okla Agency Code |
'012' |
Title | Field key to larvae in pecans |
Authors |
Mulder, Phil. Arnold, Donald C. |
Publisher | Oklahoma Cooperative Extension Service |
Publication Date | 2004-07 |
Publication type |
Handbook |
Subject |
Pecan--Diseases and pests--Oklahoma. Larvae--Identification. |
Purpose | This key is designed to serve as a guide to identification of the more typical larvae of the common insect species found in pecans and on pecan trees in Oklahoma. |
Notes | posted by Oklahoma Forestry Services |
Series | OSU fact sheets ; F-7163 |
OkDocs Class# | Z2155.5 F454l 2004 |
Digital Format | PDF, Adobe Reader required |
ODL electronic copy | Downloaded from agency website: http://www.forestry.ok.gov/Websites/forestry/Images/Field%20Key%20to%20Larvae%20in%20Pecans.pdf |
Rights and Permissions | This Oklahoma state government publication is provided for educational purposes under U.S. copyright law. Other usage requires permission of copyright holders. |
Language | English |
Date created | 2013-02-08 |
Date modified | 2013-02-08 |
OCLC number | 890221872 |
Description
Title | Field Key to Larvae in Pecans 1 |
Full text | Division of Agricultural Sciences and Natural Resources • Oklahoma State University F-7163 Oklahoma Cooperative Extension Fact Sheets are also available on our website at: http://www.osuextra.com Field Key to Larvae in Pecans Phil Mulder Extension Entomologist Don C. Arnold Survey Entomologist This key is designed to serve as a guide to identification of the more typical larvae of the common insect species found in pecans and on pecan trees in Oklahoma. The identifying characters used are based upon those found on full-grown or nearly full-grown larvae and may not necessarily occur on newly hatched larvae. If the larva in question does not fit the proper description furnished, recheck the specimen with the key. If it continues to key out improperly or is not one of the species listed, and proper identification is desired, place the larva in a small bottle containing 70% alcohol and mail to: Department of Entomology and Plant Pathology, Oklahoma State University, Stillwater, Oklahoma 74078. Please do not send specimens for identification unless they are causing or suspected of causing damage to the crop. Please include information as to the type and amount of damage noted as well as the date and community where the larva was collected. This information will assist in getting a more accurate and rapid reply to your questions. Some insects found on pecans cannot be identified with this key. This would include adult insects, closely related organisms, and such insects as aphids and phylloxera, which do not have a larval stage. Be sure you have insect larvae before attempting to use this key. All insect larvae normally found on pecans are included in this key. This key should be used primarily for larvae on pecans, but should be moderately accurate for larvae on walnut trees, also. Keys for other crops are available and can be obtained from the local county Extension office. Survey Methods Most pecan insects should be reported as the number per nut cluster or per tree. In the early season, the pecan nut casebearer should be reported as the number of eggs or larvae per 100 clusters. The color of the eggs should also be reported. After the nuts set, the number of damaged nuts per 100 clusters should be reported. Depending on the size of the grove, at least 50 clusters should be inspected. The hickory shuckworm should be reported as the number of damaged nuts per 100 nuts to give the percentage infestation. Pecan weevil surveys are made by jarring the tree and counting the weevils that fall. This is much easier if a light colored cloth or plastic sheet is placed under the tree. This should be reported as the number per tree or limb. Also, the size of the tree should be reported. Larvae in the nuts should be reported as the percentage of nuts infested. Adult emer-gence can be checked with screen wire cages placed under infested trees about mid-summer. Leaf-feeding larvae should be reported as light if very small numbers are present and little damage has occurred. If noticeable damage has occurred, it should be reported as the percentage of defoliation. The fall webworm can be reported as the number and size of webs per tree and the percentage of trees infested in the immediate area. 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 head is yellow to brown. 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. Pecan Nut Casebearer (Acrobasis nuxovrella) The body color is pale borwnish-yellow to light gray brown. The head is reddish-brown with deeper brown spots. They are up to 5/8 inch in length when mature. Over-wintering larvae feed on the buds and bore into young shoots in spring. The first generation larvae attack the young nuts in late spring, often webbing them together. Second generation larvae at-tack larger nuts in early summer. A third generation occurs later, but does little damage. Walnut Caterpillar (Datana integerrima) Young larvae are reddish with narrow yellowish or gray-ish lines, which extend the entire length of the body. Mature larvae are black with only two grayish lines on the back and two on the sides. Many soft, fine, long, grayish hairs cover the entire body. They may be up to 1 1/2 inches in length. They feed on leaves, in groups, and do not form webs on the leaves. There are two generations per year. Fall Webworm (Hyphantria cunea) These larvae vary from light buff to near black. They are covered with long light-colored hairs. They may be up to 1 1/4 inches long when mature. They make large webs on the trees and live and feed in them. There are two generations per year. Some authorities recognize two species; H. cunea and |
Date created | 2013-02-08 |
Date modified | 2013-02-08 |