158 EXPEEIMENT STATION EECORD. 



majority of full grown first brood larvae are 'found between June 18 and July 

 10, and tbe moths from these from July 1 to August 1. First brood larvae may 

 be found in the mouth of August, but of those which emerge later than the last 

 third of July, only a small percentage pupate and produce a second generation ; 

 most of them go into their overwintering cocoons and do not pupate until the 

 following spring. Our observations show eggs from the second brood moths 

 as late as August 23 but from other data and observations from other stations, 

 we may conclude that they continue to be laid at least until the middle of 

 September. We have found and recorded full grown second brood larvae in 

 small numbers before the first of August and others still in the fruit after the 

 first week in October. . . . The maximum number of second brood larvae 

 reach maturity in the month including the latter half of August and the first 

 two weeks of September. . . . We have no evidence which would indicate 

 the presence of even a partial third brood in this locality." 



Remedial measures and methods of application are considered at some length 

 and exi)eriments rejjorted which emphasize the impoi'tance of spraying. It is 

 recommended that the first application, consisting of l* to 2 lbs. arsenate of 

 lead or 5 to 10 oz. of Paris green, with or without Bordeaux, bo given when 

 the petals have nearly all fallen but before the calyx closes or the fruit drops. 

 The second application should be made a week or 10 days later, Bordeaux 

 being added. It is thought that ordinarily later treatments will not be neces- 

 sary, although often advisable. 



Two important leaf-miners, C. O. Houghton (Delaicare 8ta. Bui. 87, pp. 

 3-Jo, figs. 3). — The first part of this bulletin is devoted to the apple leaf-miner 

 {Tischcria maUfolicUa), a preliminary account of remedies for which has been 

 previously noted (E. S. R., 19, p. 451). 



Although described nearly 50 years ago and apparently of wide distribution, 

 the species has not become of much economic importance until within the 

 past 3 or 4 years. Winter is passed in the larval state, the full grown larvae 

 remaining in their silk-lined mines in leaves on the ground. Pupation takes 

 place early in the spring, in Delaware usually late in March or early in April, 

 and a little later the moths emerge. " The first mines are to be found late in 

 May, and the moths from this brood of larvae emerge late in June. . . . The 

 second brood reaches maturity about a month later, the moths emerging late 

 in July or early in August. A third brood evidently matures about September 1, 

 while the larvae of the fourth brood pass the winter in the leaves on the ground." 

 Technical descriptions are given of the several stages of the insect. A species 

 of Urogaster, probably tiscJicricc, and of Eulophus, as well as several other 

 parasites have been bred in Delaware from this insect. 



As previously noted the pest can readily be controlled by plowing under the 

 leaves and other debris, beneath and near the trees, late in the fall, or in early 

 spring before the moths emerge. 



The blackberry leaf-miner {Metallu.'^ riibi), the second insect pest considered, 

 was a source of injury to a field of dewberries at Dover in 1905, a large per- 

 centage of the leaves being infested. Infestation since, however, has been to 

 a much smaller extent. The species has been recorded from Illinois. Missouri, 

 New York, Rhode Island and from Canada. It is thought to pass the winter 

 as a larva or pupa within its cocoon in the ground. Oviposition, in a normal 

 season, appears to commence late in May. In 1906, the sawflies were abundant 

 and apparently ovipositing on J\Iay 30, a few small mines being observed on 

 this date in some of which larvae were found, which measured 2 nun. or more 

 in length. The larvae of the first brood apparently reached maturity before the 

 end of June, and those of the second late' in July or early in August. Their 

 mine is said to be without definite shape, being sometimes elongate, sometimes 



