. Annual report of the Commissioner of Agriculture ... Agriculture -- New York (State). The Currant-Stkm Girdi^er. 51 year had developed full grown borers; in most cases the eggs ap- parently did not hatch, as no tunnel had been begun in the pith, but in some cases the borers got nearly half grown before they succumbed. As Mr. Marlatt stated, the reason for this great mortality is not apparent. He suggested that it might be due to the fact that the cultivated currant, on account of its difference in growth or greater luxuriance, is not as suitable to the insect as wild currants or allied plant
. Annual report of the Commissioner of Agriculture ... Agriculture -- New York (State). The Currant-Stkm Girdi^er. 51 year had developed full grown borers; in most cases the eggs ap- parently did not hatch, as no tunnel had been begun in the pith, but in some cases the borers got nearly half grown before they succumbed. As Mr. Marlatt stated, the reason for this great mortality is not apparent. He suggested that it might be due to the fact that the cultivated currant, on account of its difference in growth or greater luxuriance, is not as suitable to the insect as wild currants or allied plants, which were presumably its original food plants. Another explanation of this great mortality may be the fact that an unfertilized female will lay eggs and girdle the shoots as freely as any other female. We dem- f^^^^v—'w^-.^ ^ ?- castrated this fact in our cages last *''*^ year, but we were not able to definitely determine whether these unfertilized eggs hatched or not. However, the fact that there is such a great mortality among the eggs and young grubs of this insect, is of but little practical importance to the cur- rant grower, for in the girdling of the shoots, the pest does its principal injury. Extent of the tunnels of the borer ^ and its preparations for the winter.—The grubs begin their work of tunneling down the pith of the girdled shoot as soon as they hatch in the latter part of May. Although the borer continues to work in the pith for about three tunnel rarely extends more thansix inches from the point where the shoot was girdled. In one instance where three shoots branched off, as shown in figure 19, a borer tunneled down to the base of one shoot and then across the main stem and part way up another shoot, where it met its death from the attacks of one of its enemies. About September ist, the borer begins to make preparations for the winter a ad for its further transformations- It cleans out the. q. — iiioois iplit ipin to sko"M th
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