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Home My WebLink AboutAspen Scale in Vail Aspen Scale in Vail �v yu r� 0 r ��r � � Another pesky insect has emerged in Vail. After �— r --a � �:� .� ��- � � �� ' �� ik, � r �� years of contending with the mountain pine beetle y� �, .,. » ��ti and its deadly impact on lodgepole pines, followed � ��`� ` T � • ,��; �- � ,�� ;� .� `` by the discovery of pine needle scale, which . . ,� e, , weakens spruce trees, now there is aspen scale. � , °�' '^° ' w . , ,�`� Rt ,�� These insects con re ate on the bark of as en trees � � �' '�` 9 9 P ��r ��^. �� :' and drain the tree's nutrients and water supply. Over � � a � �°s,�� - several years, the bark begins to split and the tree ` "`�� *� �; � '�"� z �� ,.~ _ ' �' � eventually dies. �' � �. �4�� • � �.� � � . tt�, ,, ,� '� � f �':� !a` `P' f ..'�a� �,i�,; �' *» Also called Willow Scale and Poplar Scale, it is � �N � . . � � � 7��',, �" � �. antici pated that this is a non-native s pecies, �� y • .` 4 �� introduced from Eurasia. These insects have been � ' ' �{ t `''�"wa` ��'' �-�` ' found in western and central Colorado as well as in ,' �� ` ��'�'" � "''-' 1 ' , , 1. , � .,4 V � .''�;, parts of Idaho. At this time in Colorado, the insects ; �' , � �h'; � '� have generally only impacted trees planted as '' � �` ' ,;,� �`�:�'� `y' ` landscape trees. The native aspen stands are � '� °�"�•� � " •'r y,� .. �}� � generall y unaffected. However, in some areas of - j„�,' ��,,��, ; � , Idaho, native stands have been impacted, increasing � , �;�'�'°q�;.,F the importance of early control here in Colorado. � ; � ,: ¢ 4�� o y�' � . � R�� Identification �'� ` '� ''''� • �:-. Aspen scale are light in co�or, similar to the color of � � -' � ,�.� � Y as en bark. Heavier infestations tend to be a dark ' �` � ' - � ` � grey color. The insects can be found on the primary � _ `��p �� #;;� �'iH; trunk and smaller diameter branches from ground � ; -'� � '�- -� x-� .�% level to high in the crown of the tree. On severe � Y�f{± :M� �� -;k'. infestations, a white cotton-like growth can also be �' ' ` ' - ' ' �`�''^ ''�`' "'''"�x " � found. These are woolly aphids, which are a sign of Aspen scale appear as gray areas with a a tree under stress. sandpaper-like texture. f�' �' �:� �'�, � Life Cvcle �� + -.� � �� ''' + Aspen scale (Diaspidiotus gigas) is an armored ° � insect. Eggs hatch in the spring/early summer. } � . The offspring, called "crawlers" move to a ` ��, � different part of the tree or to new trees by wind, * ;� ` birds or where branches are touching. The � �� ,,, , '; Tx - crawlers find a dean patch of bark, and create a � � , shell where they feed and spend the winter. ` ' � :;,. Mating occurs in the early spring, and the cycle f'�' � �� re eats. '� ° p _ .� - � � __ � The small orange dots are recently hatched "crawlers"moving over female scales. They are ' ''�` looking for a clean patch of bark to inhabit. Control Options If aspen scale is found, it is important that homeowners take immediate measures in order to prevent the spread of these insects. All options are best performed between late April and June to coincide with the insect's breeding cycle. Heavy Infestations `t:x J,x :� � '�;� a �` a �� Trees that are heavily infested with Aspen Scale t y�� `� ' '� �+��`� will have significant areas where the scale insects ` ' � ��'``� '� '� t '� fully cover the tree bark. They will be darker gray � �- - �'��r�,,� �^ � in color, and have a sandpaper-like appearance. •;�. ,��:� ��,_E _ ' , � 5�; � > , ,��. #a� In addition, the bark may be split, may have � . �`` '� ` <�� ,�,.� become soft or have a "bubbled" appearance. �� -� > �� ' �i �� ,_k��. „ Trees that are heavily infested should be ;:�� ,�x=' � ,�� '; r�, �•;,, ,� removed. There are no known successful ;' ,` '��,'. ;k�r.�r �`' �� treatment options and leaving the trees in place �''� � � �.��,;:�� i° only provides more breeding capability which � �� .��s �� could impact healthy trees nearby. , �t�' : �• �� 'i��3- � t.l.,�. �� .;.� � �- - : �:�w �: ,�, ' � Mild to Medium Infestations + , ��5: - ' ��'� " • There are treatments that have been successful . � � ,_ _ ,�r. -� ' '• "`"` �` �. � � �M on trees with mild or medium infestations. � -.. . 4 �. �, �,., �"�■If '" � °'� - � �' :-4 �� , Options include insecticides, horticultural oils and Left untreated,the tree�s bark can split,��bubble�� even hand removal. Insecticide options are extremely limited, and the town recommends that and/or soften,e�entua�ly leading to deatt,. insecticide treatments should be performed by a licensed commercial pesticide applicator. Other Aspen Pests There are numerous pests that impact aspen trees including -.,,.., aphids, cytospora canker and oystershell scale. Aphids tends to ��"' �`.� c a u s e t h e b l a c k r e s i d u e o f t e n f o u n d o n a s p e n b a r k a n d o n objects beneath the tree. Cytospora canker results in an orange ,� discoloration on the bark and subsequent softening of bark tissue. Oystershell scale can be mistaken for Aspen Scale, and is distinguished by an elongated "oyster-type" shell. Treatments � � �,.y for Oystershell scale are similar to Aspen Scale. The best prevention for Aspen Scale and other pests is to ensure � � � healthy trees that are properly spaced and receive adequate ,��,;„ _,., � moisture. Trees are typically capable of fighting off minor pests. ��4� �� -� H o w e v e r, w h e n g r o w i n g i n a s t r e s s f u l e n v i r o n m e n t, t h e y c a n _� : ' � :_:� eventually lose their ability to resist. �: i;�tt' �: � �. Homeowner Assistance � u�� As with past infestations, the town will continue to offer a free .,.. inspection service for property owners whdd like assistance in " evaluating the health of their trees. Consultations with tree care '�•. professionals are also recommended. For a Dead or Diseased —� Tree Removal permit, go to www.vailgov.com. The town offers � � curbside pickup of any tree removed under this permit. . };� - ,-,� For more information, contact the Public Works Department at �, `� � 479-2158, or to make an appointment for a property inspection, e-mail treehealth(a�vailqov.com The bark of a healthy aspen tree,unaffected by Aspen Scale.