VISUAL STIMULI INFLUENCING ORIENTATION BY LARVAL GYPSY MOTH, LYMANTRIA DISPAR (L.)

1992 ◽  
Vol 124 (2) ◽  
pp. 287-304 ◽  
Author(s):  
D.B. Roden ◽  
J.R. Miller ◽  
G.A. Simmons
Keyword(s):  
Populus Tremuloides ◽  
Gypsy Moth ◽  
Lymantria Dispar ◽  
Field Experiments ◽  
Quercus Rubra ◽  
Visual Stimuli ◽  
Betula Papyrifera ◽  
White Birch ◽  
Larval Instars ◽  
Real Tree

AbstractIn laboratory and field experiments involving artificial and real tree trunks, all larval instars of gypsy moth [Lymantria dispar (L.)] crawling on a horizontal surface were influenced by the diameter, height, and species of a tree. For most larval instars, black artificial tree trunks were preferred to white trunks. The influence of the diameter and height of a host on larval attraction was examined with cardboard columns. The degree of larval attraction to a column of a certain diameter and height was positively correlated with the angle at which the column was presented. Significantly more larvae were attracted to bolts of red oak (Quercus rubra L.) than to white birch (Betula papyrifera Marsh.) or trembling aspen (Populus tremuloides Michx.). The implications of these findings and their possible effects on host colonization are discussed.

scholarly journals Effects of Gypsy Moth Defoliation on Softwood and Hardwood Growth and Mortality in New Brunswick, Canada

2007 ◽  
Vol 24 (2) ◽  
pp. 138-145 ◽  
Author(s):  
Chris Richard Hennigar ◽  
David A. MacLean ◽  
Chris James Norfolk
Keyword(s):  
New Brunswick ◽  
Populus Tremuloides ◽  
Gypsy Moth ◽  
Tree Mortality ◽  
Abies Balsamea ◽  
Growth Patterns ◽  
Betula Papyrifera ◽  
Growth Reduction ◽  
White Birch ◽  
Insecticide Spray

Abstract The first major European gypsy moth (Lymantria dispar L.) outbreak occurred in central New Brunswick, Canada, on over 3,000 ha of forestland, from 2001ߝ2003. The outbreak was severe enough to result in considerable landowner concern and a privately funded aerial insecticide spray program to protect trees. Defoliation was unexpectedly severe on several tree species thought to be resistant or immune, as indicated from studies in the northeastern United States. Fifty plots (564 trees) were established and measured for standard mensurational characteristics, defoliation, and annual tree mortality, and after the cessation of defoliation, 44 trees were destructively stem analyzed to determine growth patterns. Balsam fir (Abies balsamea [L.] Mill.) with defoliation of more than 75% sustained specific volume increment reduction averaging 55% and 25% mortality after 2 years of severe defoliation. Red oak (Quercus rubra L.) sustained about 40% growth reduction, similar to results of previous studies. However, white birch (Betula papyrifera Marsh.) and trembling aspen (Populus tremuloides Michx.), with more than 75% defoliation for 2 years, sustained 43ߝ48% growth reduction, higher than in previous studies, and 4ߝ12% mortality. The gypsy moth range in Canada appears to be gradually expanding beyond previous climatic (cold winter temperature) limitations, and these results will help to predict future impacts.

Influence of burlap-band colour on larval, pupal, and egg-mass counts of Lymantria dispar (Lepidoptera: Lymantriidae)

2003 ◽  
Vol 135 (6) ◽  
pp. 869-877
Author(s):  
David B. Roden
Keyword(s):  
Gypsy Moth ◽  
Lymantria Dispar ◽  
Field Experiments ◽  
Quercus Rubra ◽  
Egg Mass ◽  
Egg Masses ◽  
Band Position ◽  
The Mean ◽  
Pupation Site ◽  
Selection Of

AbstractThis paper describes the effect of the colour of burlap bands (black versus naturally coloured or tan burlap) affixed to red oak, Quercus rubra (L.) (Fagaceae), and how it influences selection of larval resting site, pupation site, and egg-mass counts of gypsy moth, Lymantria dispar (L.). In field experiments with half black and half tan burlap bands, the mean number of larvae, pupae, and egg masses were significantly greater under the black section of burlap. Individual burlap bands composed of either black or tan burlap affixed to separate trees produced similar significant results for larvae and pupae. When two burlap bands composed of opposite colours (black versus tan) were affixed to the same tree, significantly more larvae were found under the upper band, regardless of colour. In contrast, pupa and egg-mass densities were significantly greater under black bands, regardless of band position.

Photosynthetic and morphological responses of white birch, balsam poplar, and trembling aspen to freezing and artificial defoliation

Botany ◽  
2013 ◽  
Vol 91 (6) ◽  
pp. 343-348 ◽  
Author(s):  
Rongzhou Man ◽  
Pengxin Lu ◽  
Steve Colombo ◽  
Junlin Li ◽  
Qing-Lai Dang
Keyword(s):  
Populus Tremuloides ◽  
Betula Papyrifera ◽  
Populus Balsamifera ◽  
Trembling Aspen ◽  
White Birch ◽  
Continuous Growth ◽  
Balsam Poplar ◽  
Warming Climate ◽  
Morphological Responses ◽  
Spring Frosts

Comparative stress resistance of 1-year-old white birch (Betula papyrifera Marsh.), balsam poplar (Populus balsamifera L.), and trembling aspen (Populus tremuloides Michx.) seedlings was evaluated after exposure to freezing or defoliation. Photosynthesis in leaves surviving freezing (−5 °C) declined immediately after treatment, but nearly fully recovered within 3 weeks. Defoliation did not significantly increase photosynthesis in the remaining leaves. Refoliation occurred after freezing that killed terminal shoots and released current buds from apical dominance, while new leaves of larger size were produced through continuous growth of terminal shoots in 50% or 100% defoliation. Freezing and complete defoliation significantly reduced diameter and height growth in all species, whereas 50% defoliation did not affect growth. These results indicate some of the physiological and morphological responses to foliage loss in broadleaved boreal species that can help to maintain growth and productivity under a warming climate, which may result in more frequent damaging spring frosts and insect defoliation.

scholarly journals Efficacy and speed of action of selected plant protection products on Lymantria dispar in laboratory conditions

2017 ◽  
Vol 18 ◽  
pp. 62 ◽  
Author(s):  
Z.D. Zartaloudis ◽  
M.D. Kalapanida ◽  
E.I. Navrozidis
Keyword(s):  
Bacillus Thuringiensis ◽  
Gypsy Moth ◽  
Lymantria Dispar ◽  
Plant Protection ◽  
Plant Protection Products ◽  
The Other ◽  
Larval Instars ◽  
Laboratory Conditions ◽  
Bacillus Thuringiensis Subsp

In this study some selected insecticides were evaluated for their effect on gypsy moth Lymantria dispar L., (Lepidoptera: Lymantriidae) under laboratory conditions. Diflubenzuron, methoxyfenozide, triflumuron, fenoxycarb, fenoxycarb + lufenuron, Bacillus thuringiensis 50% subsp. kurstaki + Bacillus thuringiensis 50% subsp. aizawai, Bacillus thuringiensis subsp. aizawai and spinosad were used in the recommended concentration, against the 1st, 2nd, 3rd and 4th larval instars of L. dispar. The effectiveness of the above insecticides as well as the speed of action (LTime50 and LTime90) expressed in days, were examined in detail. Spinosad and methoxyfenozide presents a relatively higher speed of action in relation to the other insecticides. LTime50 of spinosad and methoxyfenozide did not differ significantly among the first three larval instars and ranged from 0 to 0.61 and 1.13 to 1.74 days, respectively. Regarding IGRs, the mixture (fenoxycarb + lufenuron) and triflumuron were the most effective in relation to the other IGRs tested. Moreover, Bacillus thuringiensis toxins were effective only against the first two larval instars.

Defoliation by Gypsy Moth (Lepidoptera, Erebidae) Induces Differential Delayed Induction of Trichomes in Two Birch Species

2020 ◽  
Author(s):  
Sawako Matsuki ◽  
Rika Toki ◽  
Yoko Watanabe ◽  
Kazuhiko Masaka
Keyword(s):  
Leaf Area ◽  
Gypsy Moth ◽  
Lymantria Dispar ◽  
White Birch ◽  
Gypsy Moths ◽  
Birch Trees ◽  
Leaf Surfaces ◽  
Mechanical Cutting ◽  
And Control ◽  
Light Shading

Abstract Outbreaks of the gypsy moth (Lymantria dispar japonica Motschulsky) cause serious defoliation in birch. A single year of defoliation has no significant impact on the trees, whereas continuous defoliation events could be fatal. How birch species avoid serious damage caused by gypsy moth outbreak is yet to be revealed. Trichomes on leaf surfaces of birch trees are an effective antiherbivore defense strategy. We examined a 1-yr delayed induction of glandular (GT) and nonglandular trichomes (NGT) on leaf surfaces caused by stress in white birch (Betula platyphylla Sukaczev var. japonica [Miq.] Hara) and monarch birch (Betula maximowicziana Regel). Saplings were subjected to four treatments in June 2009: herbivory (50% of the leaf area was grazed by gypsy moths), mechanical cutting (50% of the leaf area was cut using scissors), shading (50% light shading with a black sheet), and control (covered with a net to prevent herbivory). Then, the density of GT and NGT on early leaves was determined in April 2010. In both birch species, the density of GT was higher in herbivory than in other treatments. The density of GT due to mechanical cutting was higher than that in the control, but only for white birch. However, the density of NGT was lower after mechanical cutting than in other treatments for white birch. There were no differences in the density of NGT among treatments for monarch birch. These results show that 1-yr delayed induction of GT by herbivory was stronger in white birch than in monarch birch.

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