Dying-back in all its forms is a common result of defoliation by insects, e.
When, by the breaking of the branch above the insertion of the dormant bud--or by pruning, defoliation by insects, etc.
In our own latitudes, as we all know, the defoliation of the trees is caused by the approach of cold weather, which decreases the activity of the roots, so that the leaves become dry and lifeless.
The defoliation caused by walkingsticks generally occurs on upland sites in stands which are not of high value or intensively managed.
Repeated defoliation causes growth loss, reduces mast crops, and will eventually kill the tree.
In commercial stands the growth loss caused by several years of 50% defoliation by this insect can amount to 1/3 of the expected growth.
Heavy defoliation for two or more years can weaken trees and make them more susceptible to other insects and diseases, particularly when associated with drought.
Illustration: Wilting foliage and defoliation of elms caused by Verticillium wilt.
Usually such outbreaks coincide with periods of drought which increase the impact of defoliation on the host.
Rarely is the defoliation severe enough to kill the seedlings, but it undoubtedly has an impact on growth.
Three successive years of complete defoliation will result in death.
While infestations usually subside before many trees are killed, heavy defoliation reduces the tree's growth and vigor.
The forest tent caterpillar has caused repeated serious defoliation of hardwood forests throughout North America.
Infestations are generally more severe in the South, where the insect has two generations per year causing two periods of defoliation in a single year.
Premature defoliation and death of branches usually occurs, causing the crown to appear thin and sparse.
The Buckeye Leaf Stem Borer Defoliationof Oak Trees by Dryocampa senatoria in Perry County, Pa.
The aphids were very numerous and unfortunately caused the defoliation of all the currants with the exception of the blacks.
Caterpillars, grubs, and beetles specialize on defoliation and feed upon the leaves, the lungs of the trees.
The partialdefoliation of the tree is devitalizing, and the loss of all its leaves commonly kills it.
Pecan trees at times suffer sufficient damage from the black pecan aphid[15] to cause considerable defoliation (Fig.
I have seen hordes of beetles gather in these trees in July and August, skeletonizing the leaves until the defoliation reached 40% or more.
You will note the conspicuous defoliation of the vines on the fence rows.
The evidence indicates rather that it attacks trees that are already somewhat weakened by defoliation or other injury.
Very often this premature defoliation results in the production of a new crop of leaves and some shoot growth.
A husk blight appears to affect Persian walnuts in some places, and nut production is very seriously affected among black walnuts by defoliation prematurely, either because of drought or leaf-spot.
Early defoliation appears to be the cause of poor filling in wet seasons.
Also shriveled kernels are the result of defoliation by early frosts which may be very local and affect some trees and not others.
In a few plantings a condition causing some prematuredefoliation has been observed at infrequent intervals.
These sucking insects are small in size and may be overlooked until premature defoliation takes place.
A leaf spot disease has been observed but has caused no appreciable defoliation and no control measures have been thought necessary.
The above list will hopefully give you a few useful examples demonstrating the appropriate usage of "defoliation" in a variety of sentences. We hope that you will now be able to make sentences using this word.
