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In attempting to understand the reasons for this situation, I think a brief 

 review of what we know about the red-banded leaf roller is in order at this time. 

 First of all, the red-banded leaf roller has a history of being cyclic, that is, 

 being abundant for a few years and then fading away for a few years only to pop 

 up again at some future date. Secondly, successful control of this pest is de- 

 pendent on thorough coverage, with particular emphasis on under-leaf coverage 

 in all parts of the trees. The switch to air-blast type machines has increased 

 our problem of getting thorough coverage. Pruning practices are also an important 

 factor in the spray coverage that we achieve. If pruning is haphazard or neglected 

 and the trees are allowed to become too thick, adequate coverage may be difficult. 

 Thirdly, there has also been some tendency for growers to reduce gallonage and 

 amount of toxicant per tree to minimum levels in recent years. 



However, the factors I have just enumerated do not fully explain the serious 

 difficulties some growers have gotten into with respect to control of the red- 

 banded leaf roller during the last two seasons. TDE which has done such a good 

 job for us in the past appears to be falling down even where thoroughly applied 

 at the proper times with the correct dosage. In New York and some other states, 

 it has been shown that some leaf roller populations have developed a tolerance 

 to TDE, in other words, the red-banded leaf roller is resistant to TDE. This 

 appears to be the case in orchards where TDE has been used for several years. 

 In Massachusetts, we believe that leaf roller resistance to TDE is the factor 

 responsible for our recent troubles in controlling this pest in some orchards. 



Life History 



Before discussing control program, let's briefly review the life history 

 of the red-banded leaf roller. The insect overwinters as a pupa on the ground 

 in trash and debris under trees. Moths emerge in the spring soom after the first 

 green tissue shows in the buds. The greatest numbers are present from late delayed 

 dormant through bloom. Egg laying begins soon after emergence and usually continues 

 through bloom. Eggs are deposited chiefly on the bark of the trunks and main scaf- 

 fold limbs. Hatching usually starts about petal fall and the majority hatch over 

 a period of 10-14 days after bloom. First brood larvae feed on the under surface 

 of leaves especially along the mid-rib or along one of the larger veins. Some 

 migrate to and injure developing fruit. Fully grown larvae pupate in a protected 

 site such as a rolled leaf or between leaves on which they fed. 



First brood moths begin to emerge about the second week in July and are most 

 numerous during the last two weeks of the month. They disappear rapidly in early 

 August but an occasional moth may be seen as late as early September. Egg deposi- 

 tion by the first brood moths begins shortly after emergence and continues until 

 late August, although most second brood eggs are laid in late July. These eggs 

 are chiefly deposited on the upper surfaces of leaves and are very difficult to 

 find. Second brood larvae feed on the undersides of leaves as with the first 

 brood. However, later nearly all of them move about the tree and feed on the fruit. 



During some seasons, some second brood larvae pupate and the moths that emerge 

 may lay eggs for a partial third brood. |j^ 



Recommendations for control of the red-banded leaf roller in 1960 will be 

 discussed in the next issue of FRUIT NOTES. 



W. D. Tunis 



Extension Entomologist 



