TREE INSECTS AND THEIR CONTROL 201 



ELM 



LEAF CHEWING INSECTS 

 Elm-leaf Beetle 



Habits Attacks all Elms, especially 



and the English Elm. Causes 



Damage, leaves to fall; if not checked, it 

 brings about complete loss of 

 leaves and if repeated sufficiently often 

 will cause the death of tree. 



The first sign of damage is the appear- 

 ance of irregular holes in leaves in early 

 spring. These come from attacks by the 

 full-grown beetle, which has just come 

 from its winter quarters in barns, sheds 

 and similar shelter. At this time eggs are 

 laid on the under side of the leaves. In 

 June these eggs hatch into larvae or grubs 

 which grow to be one-half inch in length; 

 the larvae feed on the leaves, giving the 

 leaves the appearance of skeletons or 

 lacework. Within 15 to 20 days after 

 hatching the larvae develop into pupae, 

 or young beetles, which are to be found 

 at the foot of the tree. Just before this 

 change the larvae may be seen crawling 

 down the trunk. In another week the 

 young beetles become fully grown. 



The eggs are orange-yellow in color, 

 and occur in clusters of from five to 

 twenty, in irregular rows on the under 

 side of the leaves. The larvae are yellow- 

 ish black to blackish. The pupae are 

 orange-colored. 



Combined action on the part of the entire neighborhood is essential in undertaking 

 the destruction of the Elm-leaf beetle. Unless all trees are treated, the results will 

 be without value, as the beetles will travel from infested trees to those which may 

 have been treated. Another factor in the importance of cooperative action is that 

 expensive spraying apparatus is required for trees as large as Elms and this appar- 

 atus should be owned by the town or city government or by a number of individual 

 property owners. 



Remedy. The best control is by the use 

 of arsenate of lead, by spray- 

 ing, whenever and as often as there are 

 signs of attack. This poison should be 

 applied to the foliage in the early spring, 

 just after the buds have burst, and again 

 two weeks later. If rains fall after the 

 spraying it may be necessary to apply the 

 poison a third or even a fourth time. The 

 poison must reach the under side of the 

 leaves to be effective against the eggs and 

 the larvae. The first spraying is intended 

 to kill the adults and prevent the laying of 

 eggs; the later sprayings are additional 

 safeguards against possible survivors. 



To destroy the pupae at the base of the 

 tree scalding water, thick soapsuds or a 

 solution of kerosene should be poured 

 over them in liberal quantities; this 

 should be used promptly and repeated 

 whenever and as often as may be neces- 

 sary until all the insects are destroyed. 

 The surface of the soil should be turned 

 by digging, to expose any insects which 

 may have buried themselves. In the case 

 of a large tree it is sometimes necessary 

 to climb to the forks of limbs and gather 

 stragglers. 



Brown-tail Moth 



Habits 



and 



Damage 



This leaf-eating insect causes 

 great damage in New Eng- 

 land and a severe attack 

 destroys leaves as fast as 

 The eggs hatch early in 

 August, after having been laid in July in 

 oblong clusters covered with brown hair 

 on the underside of the leaves. The 

 young caterpillars make tents for them- 



developed. 



Remedies. Cutting off the winter 



tents and burning them is an 

 effectual method of destroying this pest. 

 This must be done before the caterpillars 

 emerge in the spring. It is also useful to 

 spray with arsenate of lead when the 

 leaves are full grown and again when the 

 caterpillars hatch. 



