{"id":160,"date":"2014-07-16T14:48:16","date_gmt":"2014-07-16T18:48:16","guid":{"rendered":"http:\/\/site.extension.uga.edu\/pecan\/?p=160"},"modified":"2014-07-16T14:48:16","modified_gmt":"2014-07-16T18:48:16","slug":"nut-drop","status":"publish","type":"post","link":"https:\/\/site.extension.uga.edu\/pecan\/2014\/07\/nut-drop\/","title":{"rendered":"Nut Drop"},"content":{"rendered":"

Its the time of year when a few insects may rear their heads and cause some nut drop in the orchards. I refer here mostly to nut curculio\u00a0and hickory shuckworm.<\/p>\n

The nut curculio attacks immature pecans from late June through early August.\u00a0 Adults make shallow crescent shaped punctures with their snouts in the shucks of immature nuts in which they lay eggs.\u00a0 When the eggs hatch, the larvae consume the insides of the pecan.\u00a0 Adult feeding puncture are usually visible on damaged nuts. The curculio puncture and larval feeding within the pecan cause a bleeding brown sap (tobacco-like deposits) on the shuck of the nut at the point of entry and a premature nut drop similar to that caused by the hickory shuckworm. The damaged nuts drop from the tree, but the creamy-white legless larvae continue to feed in the dropped nuts for about two weeks before leaving the nut through a circular hole.\u00a0 The larvae form a pupal cell under the nut in the upper two to four inches of the soil.\u00a0 Adults emerge four weeks later and overwinter in ground trash or other protected places.\u00a0 This curculio produces only one generation per year.\u00a0The most common treatment for curculio is chlorpyrifos but be sure you have a problem with them before you spray since chlorpyrifos will greatly aggrevate your aphid and mite situation.<\/p>\n

When trees have a good nut crop, nut curculio damage may go unnoticed or be attributed to hickory shuckworm.\u00a0 Chemical control may be necessary when past history, jarring the trees, or knock-down sprays indicate the presence of many adults.\u00a0 Usually, trees adjacent to woods or thick hedge rows are more subject to nut curculio attack since these places provide overwintering sites for the adults.<\/p>\n

\"IMG_1307\"<\/a><\/p>\n

Symptoms of nut damage by hickory shuckworm (top 2 nuts) and nut curculio (bottom nut)<\/p>\n

 <\/p>\n

Hickory shuckworm begins attacking when the nuts are first formed in early June and continues until harvest.\u00a0 Damage by the hickory shuckworm results from the feeding activity of the larvae.\u00a0 Prior to shell-hardening, the feeding of shuckworm larvae within the nut results in premature nut drop.\u00a0 After shell hardening, larvae are confined to feeding within the shuck.\u00a0 Damage resulting from the shuckmining activities of the larvae include poor kernel development (due to the severing of vascular tissue in the shuck), shuck sticking, scarring and discoloration of the shell and delayed nut maturity.\u00a0 Except for premature nut drop, shuckworm damage usually goes unnoticed unless the shuck is cut open to reveal the tunneling of the larva within the shuck.<\/p>\n

Hickory shuckworm moths emerging in the spring, prior to nut formation, lay their eggs on pecan foliage, the galls of pecan phylloxera, and nuts of early developing hickories.\u00a0Orchards with heavy phylloxera often end up with heavy shuckworm populations as well.\u00a0Shuckworms hatching from eggs deposited on the foliage will generally die before completing their life cycle.\u00a0 However, those larvae developing within the phylloxera galls or hickory nuts are able to complete their life cycle, thus maintaining the population until nut formation occurs.\u00a0 Researchers have also reported that adult moths of the overwintering generation emerge from the shucks as late as July, August and September.\u00a0 During the summer months, female shuckworms begin to deposit their eggs on the nuts.\u00a0 After nut formation occurs, shuckworms populations usually increase with each succeeding generation.\u00a0 The number of generations per year will vary from two to five depending on location.<\/p>\n

Currently, chemical control is the most widely used method for suppressing shuckworm populations.\u00a0 Contact insecticides like chlorpyrifos are directed at the adult moths, reducing the egg-laying population but flair aphids and mites.\u00a0 Insect growth regulators like Intrepid and Dimilin disrupt larval development, and must be applied before eggs are laid for the hatchling caterpillars to be exposed before entering the shuck.<\/p>\n

Examine dropped nuts for the characteristic whitish residue around the entry hole in June and July.\u00a0 Orchards with a history of shuckworm problems should be treated at shell-hardening, as mature nuts will not drop.\u00a0 If late-season treatments are applied for pecan weevil control, they will also control hickory shuckworm.<\/p>\n","protected":false},"excerpt":{"rendered":"

Its the time of year when a few insects may rear their heads and cause some nut drop in the orchards. I refer here mostly to nut curculio\u00a0and hickory shuckworm. The nut curculio attacks immature pecans from late June through early August.\u00a0 Adults make shallow crescent shaped punctures with their snouts in the shucks of […]<\/p>\n","protected":false},"author":55,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-160","post","type-post","status-publish","format-standard","hentry","category-uncategorized"],"_links":{"self":[{"href":"https:\/\/site.extension.uga.edu\/pecan\/wp-json\/wp\/v2\/posts\/160","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/site.extension.uga.edu\/pecan\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/site.extension.uga.edu\/pecan\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/site.extension.uga.edu\/pecan\/wp-json\/wp\/v2\/users\/55"}],"replies":[{"embeddable":true,"href":"https:\/\/site.extension.uga.edu\/pecan\/wp-json\/wp\/v2\/comments?post=160"}],"version-history":[{"count":1,"href":"https:\/\/site.extension.uga.edu\/pecan\/wp-json\/wp\/v2\/posts\/160\/revisions"}],"predecessor-version":[{"id":161,"href":"https:\/\/site.extension.uga.edu\/pecan\/wp-json\/wp\/v2\/posts\/160\/revisions\/161"}],"wp:attachment":[{"href":"https:\/\/site.extension.uga.edu\/pecan\/wp-json\/wp\/v2\/media?parent=160"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/site.extension.uga.edu\/pecan\/wp-json\/wp\/v2\/categories?post=160"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/site.extension.uga.edu\/pecan\/wp-json\/wp\/v2\/tags?post=160"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}