{"id":1091,"date":"2017-03-13T15:11:25","date_gmt":"2017-03-13T22:11:25","guid":{"rendered":"https:\/\/extension.wsu.edu\/wam\/?page_id=1091"},"modified":"2024-11-22T14:51:42","modified_gmt":"2024-11-22T22:51:42","slug":"weevil-biology-and-management-in-berries","status":"publish","type":"post","link":"https:\/\/extension.wsu.edu\/wam\/2017\/03\/13\/weevil-biology-and-management-in-berries\/","title":{"rendered":"[Archived]: Entomology Program Update: Weevil Biology and Management in Berries"},"content":{"rendered":"<p>[row][column][textblock]<\/p>\n<p style=\"text-align: right\"><strong>Volume 5 Issue 10<\/strong><\/p>\n<p><strong>Beverly Gerdeman, Entomologist at WSU-NWREC&nbsp;and Hollis Spitler<\/strong><br \/>\n<strong>Email: <a class=\"nonblock\" href=\"mailto:bgerdeman@wsu.edu\">bgerdeman@wsu.edu<\/a><\/strong>[\/textblock][textblock]<\/p>\n<h2>Identifying Weevil Damage<\/h2>\n<ul>\n<li>Sometimes but not always, there is leaf notching.<\/li>\n<li>Leaf notching \u2013 half circles cut out of leaf margins (Fig. 1).<\/li>\n<li>Evidence of chewing or girdling roots (Figs. 2 &amp; 3).<\/li>\n<li>Plants look weak, diseased or water stressed.<\/li>\n<li>Sampling for root weevil larvae by digging is necessary to verify infestations (Fig. 4).<\/li>\n<\/ul>\n<p>[\/textblock][\/column][\/row][row layout=&#8221;halves&#8221;][column][textblock]<\/p>\n<figure id=\"attachment_1102\" aria-describedby=\"caption-attachment-1102\" style=\"width: 480px\" class=\"wp-caption aligncenter\"><img decoding=\"async\" loading=\"lazy\" class=\"wp-image-1102 size-full\" src=\"https:\/\/wpcdn.web.wsu.edu\/extension\/uploads\/sites\/37\/2017\/03\/2016-10-s10-fig1.jpg\" width=\"480\" height=\"320\" srcset=\"https:\/\/wpcdn.web.wsu.edu\/extension\/uploads\/sites\/37\/2017\/03\/2016-10-s10-fig1.jpg 480w, https:\/\/wpcdn.web.wsu.edu\/extension\/uploads\/sites\/37\/2017\/03\/2016-10-s10-fig1-300x200.jpg 300w\" sizes=\"(max-width: 480px) 100vw, 480px\" \/><figcaption id=\"caption-attachment-1102\" class=\"wp-caption-text\"><strong>Fig. 1.<\/strong> Not all root weevil adults feed on blueberry foliage. Those that do, typically notch leaves near the ground.<\/figcaption><\/figure>\n<p>[\/textblock][\/column][column][textblock]<\/p>\n<figure id=\"attachment_1103\" aria-describedby=\"caption-attachment-1103\" style=\"width: 308px\" class=\"wp-caption aligncenter\"><img decoding=\"async\" loading=\"lazy\" class=\"wp-image-1103 size-full\" src=\"http:\/\/s3.wp.wsu.edu\/uploads\/sites\/2091\/2017\/03\/2016-10-s10-fig2.png\" width=\"308\" height=\"54\"><figcaption id=\"caption-attachment-1103\" class=\"wp-caption-text\"><strong>Fig. 2.<\/strong> Blueberry root nearly girdled into two by root weevil larvae.<\/figcaption><\/figure>\n<p>[\/textblock][\/column][\/row][row][column][textblock]<\/p>\n<h3>Sampling<\/h3>\n<ul>\n<li>Begin sampling in April for weevil larvae and pupae.<\/li>\n<li>Weevils vacate weak bushes to attack healthy adjacent plants, so sample a plant next to a weak one.<\/li>\n<li>Dig 2-3 inches in the soil near the crown to locate the white larvae and pupae easily seen in the dark soil Fig. 16).<\/li>\n<li>Continue sampling by digging midway down the shoulder of the row hill.<\/li>\n<li>Sample more than 1 plant to increase chances of finding weevil larvae and pupae.<\/li>\n<\/ul>\n<p>[\/textblock][\/column][\/row][row layout=&#8221;halves&#8221;][column][textblock]<\/p>\n<figure id=\"attachment_1104\" aria-describedby=\"caption-attachment-1104\" style=\"width: 230px\" class=\"wp-caption aligncenter\"><img decoding=\"async\" loading=\"lazy\" class=\"wp-image-1104 size-full\" src=\"http:\/\/s3.wp.wsu.edu\/uploads\/sites\/2091\/2017\/03\/2016-10-s10-fig3.jpg\" width=\"230\" height=\"408\"><figcaption id=\"caption-attachment-1104\" class=\"wp-caption-text\"><strong>Fig. 3.<\/strong> Early instar root weevil larvae collected in September 2016 next to a penny as a size reference.<\/figcaption><\/figure>\n<p>[\/textblock][\/column][column][textblock]<\/p>\n<figure id=\"attachment_1105\" aria-describedby=\"caption-attachment-1105\" style=\"width: 481px\" class=\"wp-caption aligncenter\"><img decoding=\"async\" loading=\"lazy\" class=\"wp-image-1105 size-full\" src=\"https:\/\/wpcdn.web.wsu.edu\/extension\/uploads\/sites\/37\/2017\/03\/2016-10-s10-fig4.jpg\" width=\"481\" height=\"321\" srcset=\"https:\/\/wpcdn.web.wsu.edu\/extension\/uploads\/sites\/37\/2017\/03\/2016-10-s10-fig4.jpg 481w, https:\/\/wpcdn.web.wsu.edu\/extension\/uploads\/sites\/37\/2017\/03\/2016-10-s10-fig4-300x200.jpg 300w\" sizes=\"(max-width: 481px) 100vw, 481px\" \/><figcaption id=\"caption-attachment-1105\" class=\"wp-caption-text\"><strong>Fig. 4.<\/strong> Severe root weevil damaged blueberry from feeding on the left. The blueberry plant on the right exhibits less damage and could recover. Young plantings are highly suseptable to root weevil damage.<\/figcaption><\/figure>\n<p>[\/textblock][\/column][\/row][row layout=&#8221;halves&#8221;][column][textblock]<\/p>\n<figure id=\"attachment_1106\" aria-describedby=\"caption-attachment-1106\" style=\"width: 424px\" class=\"wp-caption aligncenter\"><img decoding=\"async\" loading=\"lazy\" class=\"wp-image-1106 size-full\" src=\"http:\/\/s3.wp.wsu.edu\/uploads\/sites\/2091\/2017\/03\/2016-10-s10-fig5a.jpg\" width=\"424\" height=\"474\"><figcaption id=\"caption-attachment-1106\" class=\"wp-caption-text\"><strong>Fig. 5.<\/strong> Digging for root weevil larvae and pupae in blueberry.<\/figcaption><\/figure>\n<p>[\/textblock][\/column][column][textblock]<img decoding=\"async\" loading=\"lazy\" class=\"aligncenter size-full wp-image-1107\" src=\"https:\/\/wpcdn.web.wsu.edu\/extension\/uploads\/sites\/37\/2017\/03\/2016-10-s10-fig5b.jpg\" alt=\"\" width=\"281\" height=\"374\" srcset=\"https:\/\/wpcdn.web.wsu.edu\/extension\/uploads\/sites\/37\/2017\/03\/2016-10-s10-fig5b.jpg 281w, https:\/\/wpcdn.web.wsu.edu\/extension\/uploads\/sites\/37\/2017\/03\/2016-10-s10-fig5b-225x300.jpg 225w\" sizes=\"(max-width: 281px) 100vw, 281px\" \/>[\/textblock][\/column][\/row][row layout=&#8221;halves&#8221;][column][textblock]<\/p>\n<h3>Timing for Sampling and Spraying to Control Root Weevils in Blueberry (Table 1)<\/h3>\n<ul>\n<li>Eggs hatch in the summer so by fall they are young larvae, with few adults and no pupae (Fig. 6).<\/li>\n<li>In the fall young larvae are near the crown where they hatched.&nbsp; Concentrate spraying near the crown.<\/li>\n<li>In the fall there are no concerns about the 75-day PHI with Platinum.<\/li>\n<li>In the fall there are no worries about postbloom restrictions for Advise or Admire Pro.<\/li>\n<li>In the fall before the rains, the ground is not muddy and you can easily spray.<\/li>\n<li>Make applications before a rain to move the insecticides into the soil.&nbsp; If the ground is not wet, run irrigation before and during the application.<\/li>\n<li>Weevils are typically a chronic problem.&nbsp; Expect control to require multiple treatments across several seasons, followed by continual vigilance!<\/li>\n<li>A new label registration for Capture LFR (bifenthrin) may provide additional opportunities for controlling root weevil larvae.&nbsp; See Table 2.<\/li>\n<\/ul>\n<p>[\/textblock][\/column][column][textblock]<\/p>\n<figure id=\"attachment_1097\" aria-describedby=\"caption-attachment-1097\" style=\"width: 298px\" class=\"wp-caption aligncenter\"><img decoding=\"async\" loading=\"lazy\" class=\"wp-image-1097 size-full\" src=\"https:\/\/wpcdn.web.wsu.edu\/extension\/uploads\/sites\/37\/2017\/03\/2016-10-s10-fig6.jpg\" width=\"298\" height=\"447\" srcset=\"https:\/\/wpcdn.web.wsu.edu\/extension\/uploads\/sites\/37\/2017\/03\/2016-10-s10-fig6.jpg 298w, https:\/\/wpcdn.web.wsu.edu\/extension\/uploads\/sites\/37\/2017\/03\/2016-10-s10-fig6-200x300.jpg 200w\" sizes=\"(max-width: 298px) 100vw, 298px\" \/><figcaption id=\"caption-attachment-1097\" class=\"wp-caption-text\"><strong>Fig. 6.<\/strong> Root weevil pupa and its protective soil hibernaculum where pupation occurs. This is not a life staeto target for control since it is non-feeding and in a protected location.<\/figcaption><\/figure>\n<p>[\/textblock][\/column][\/row][row][column][textblock]<img decoding=\"async\" loading=\"lazy\" class=\"aligncenter wp-image-1100 size-full\" src=\"http:\/\/s3.wp.wsu.edu\/uploads\/sites\/2091\/2017\/03\/2016-10-s10-table1.jpg\" width=\"824\" height=\"274\">[\/textblock][textblock]*A new label for the bifenthrin soil formulation, Capture LFR, is due out in 2017 and is expected to include blueberry and be labeled for drip.<br \/>\n** Label allows use as high volume drenching application.<br \/>\n*** Advise 2F has been discontinued and replaced with Advise 4, which has a different rate.[\/textblock][textblock]<\/p>\n<h3>Field Trial<\/h3>\n<ul>\n<li>A fall field trial in 2015 was conducted in Skagit County on 21 October.<\/li>\n<li>Pre-treatment sampling verified the presence of weevil larvae but exact population size and distribution were unknown.<\/li>\n<li>The field trial consisted of 2-bush treatment plots, replicated 6 times in an RCB design to minimize variability.<\/li>\n<li>Four products were tested using a CO2 backpack sprayer (Table 2).<\/li>\n<li>Water equivalent to 250 gal\/acre was applied to the treated areas to help drive the materials down into the soil at a target depth of 2-3 inches.<\/li>\n<li>Treatments were evaluated by digging for larvae and also by using leaf notching as a secondary method of evaluation.<\/li>\n<\/ul>\n<p>[\/textblock][textblock]<img decoding=\"async\" loading=\"lazy\" class=\"aligncenter size-full wp-image-1101\" src=\"https:\/\/wpcdn.web.wsu.edu\/extension\/uploads\/sites\/37\/2017\/03\/2016-10-s10-table2.jpg\" alt=\"\" width=\"811\" height=\"281\" srcset=\"https:\/\/wpcdn.web.wsu.edu\/extension\/uploads\/sites\/37\/2017\/03\/2016-10-s10-table2.jpg 811w, https:\/\/wpcdn.web.wsu.edu\/extension\/uploads\/sites\/37\/2017\/03\/2016-10-s10-table2-300x104.jpg 300w, https:\/\/wpcdn.web.wsu.edu\/extension\/uploads\/sites\/37\/2017\/03\/2016-10-s10-table2-768x266.jpg 768w\" sizes=\"(max-width: 811px) 100vw, 811px\" \/>[\/textblock][textblock]<\/p>\n<h3>Evaluation \u2013 larvae\/pupae<\/h3>\n<p>Larvae and pupae were recovered (26 total) from one side of each bush the following April.&nbsp; Recovery was low but all 4 treatments were better than the untreated but none were statistically different from each another (Fig. 7).[\/textblock][textblock]<\/p>\n<figure id=\"attachment_1098\" aria-describedby=\"caption-attachment-1098\" style=\"width: 755px\" class=\"wp-caption aligncenter\"><img decoding=\"async\" loading=\"lazy\" class=\"wp-image-1098 size-full\" src=\"https:\/\/wpcdn.web.wsu.edu\/extension\/uploads\/sites\/37\/2017\/03\/2016-10-s10-fig7.jpg\" width=\"755\" height=\"381\" srcset=\"https:\/\/wpcdn.web.wsu.edu\/extension\/uploads\/sites\/37\/2017\/03\/2016-10-s10-fig7.jpg 755w, https:\/\/wpcdn.web.wsu.edu\/extension\/uploads\/sites\/37\/2017\/03\/2016-10-s10-fig7-300x151.jpg 300w\" sizes=\"(max-width: 755px) 100vw, 755px\" \/><figcaption id=\"caption-attachment-1098\" class=\"wp-caption-text\"><strong>Fig. 7.<\/strong> Fall treatments were evaluated in April, 6 months after treatment. NOne of hte treatements out-performed the others but all were significant;y different from the untreated. P&lt;0.05 Fisher test.<\/figcaption><\/figure>\n<p>[\/textblock][textblock]<\/p>\n<h3>Evaluation &#8211; Leaf Notching<\/h3>\n<p>Leaves with notching were counted from every bush (12\/treatment) in the spring to provide additional evidence of product performance.<\/p>\n<p>Results indicate activity but none of the treatments were any worse than the others (Fig. 8).[\/textblock][textblock]<\/p>\n<figure id=\"attachment_1099\" aria-describedby=\"caption-attachment-1099\" style=\"width: 741px\" class=\"wp-caption aligncenter\"><img decoding=\"async\" loading=\"lazy\" class=\"wp-image-1099 size-full\" src=\"https:\/\/wpcdn.web.wsu.edu\/extension\/uploads\/sites\/37\/2017\/03\/2016-10-s10-fig8.jpg\" width=\"741\" height=\"348\" srcset=\"https:\/\/wpcdn.web.wsu.edu\/extension\/uploads\/sites\/37\/2017\/03\/2016-10-s10-fig8.jpg 741w, https:\/\/wpcdn.web.wsu.edu\/extension\/uploads\/sites\/37\/2017\/03\/2016-10-s10-fig8-300x141.jpg 300w\" sizes=\"(max-width: 741px) 100vw, 741px\" \/><figcaption id=\"caption-attachment-1099\" class=\"wp-caption-text\"><strong>Fig. 8.<\/strong> Twelve bushes\/treatment were examined for leaf notching in the spring following fall treatments. Results suggest some efficacy compared with the untreated but non of the treatements were better than the others. P&lt;0.05 Fisher t test<\/figcaption><\/figure>\n<p>[\/textblock][textblock]<\/p>\n<h3>Summary<\/h3>\n<ul>\n<li>Pyrethroids such as bifethrin are non-systemic, nearly immobile in the soil, so placement is important. Typically effectiveness would result from adults crawling through the toxic barrier.<\/li>\n<li>Neonicotinoids are systemic, uptaken by the roots and provide a wider zone of protection.<\/li>\n<li>Neonicotinoids are uptaken into the roots and work best as ingestion poisons but have some contact efficacy<\/li>\n<\/ul>\n<p>[\/textblock][\/column][\/row]<\/p>\n\n        <div id=\"cahnrs-back-to-top\" class=\"cahnrs-back-to-top\" hidden aria-hidden=\"true\">\n            <a id=\"cahnrs-back-to-top-btn\" class=\"cahnrs-back-to-top__btn\" href=\"#product-top\" aria-label=\"Back to top\">\n                <span class=\"cahnrs-back-to-top__icon\" aria-hidden=\"true\">\u2191<\/span>\n                <span class=\"cahnrs-back-to-top__label\">Back to top<\/span>\n            <\/a>\n        <\/div>","protected":false},"excerpt":{"rendered":"<p>Volume 5 Issue 10 Beverly Gerdeman, Entomologist at WSU-NWREC\u00a0and Hollis Spitler Email: bgerdeman@wsu.edu Identifying Weevil Damage Sometimes but not always, there is leaf notching. Leaf notching \u2013 half circles cut out of leaf margins (Fig. 1). Evidence of chewing or girdling roots (Figs. 2 &amp; 3). Plants look weak, diseased or water stressed. Sampling for&hellip;<\/p>\n","protected":false},"author":10,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_external_link":"","_expiration_date":""},"categories":[6,14,21],"tags":[],"_links":{"self":[{"href":"https:\/\/extension.wsu.edu\/wam\/wp-json\/wp\/v2\/posts\/1091"}],"collection":[{"href":"https:\/\/extension.wsu.edu\/wam\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/extension.wsu.edu\/wam\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/extension.wsu.edu\/wam\/wp-json\/wp\/v2\/users\/10"}],"replies":[{"embeddable":true,"href":"https:\/\/extension.wsu.edu\/wam\/wp-json\/wp\/v2\/comments?post=1091"}],"version-history":[{"count":2,"href":"https:\/\/extension.wsu.edu\/wam\/wp-json\/wp\/v2\/posts\/1091\/revisions"}],"predecessor-version":[{"id":5699,"href":"https:\/\/extension.wsu.edu\/wam\/wp-json\/wp\/v2\/posts\/1091\/revisions\/5699"}],"wp:attachment":[{"href":"https:\/\/extension.wsu.edu\/wam\/wp-json\/wp\/v2\/media?parent=1091"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/extension.wsu.edu\/wam\/wp-json\/wp\/v2\/categories?post=1091"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/extension.wsu.edu\/wam\/wp-json\/wp\/v2\/tags?post=1091"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}