GARDEN PESTS IN NEW ZEALAND 



CHAPTER VII. 



Leaf-Feeding Insects. 



EIAF-FEEDING INSECTS have their mouth-parts developed for 

 the biting off and mastication of their food; such insects are, in 

 general, earwigs, crickets and grasshoppers, the caterpillars of moths 

 and butterflies, beetles and their grubs, and the grubs of saw-flies. Such 

 insects vary, not only in their period of activity, some feeding at night, 

 others during the day, but also in the manner under which they set 

 about it. Many feed exposed upon the surface of the plant, while others 

 require protection, such as is afforded by the webbing together of leaves. 

 Some feed upon the leaf epidermis only; some eat holes in the leaf- 

 surface, or gnaw irregular notches from the leaf -edge ; while the grosser 

 feeders completely devour the whole. 



Earwigs. 



In many parts of New Zealand the European earwig (Forficula 

 auricularia) causes considerable damage in gardens, while in Central 

 Otago it sometimes ruins the stone fruits. During the winter this insect 

 lies underground, where the female will be found with her cluster of 

 eggs. In the spring these eggs hatch, and the small whitish young 

 earwigs (Fig. 4, 2) emerge from the ground to feed largely upon the 

 pollen and pistils of flowers. At that time the insects and the injury 

 -they do are not very noticeable, but as the earwigs grow in size they 

 become conspicuous and extend their depredations to the foliage of 

 plants and to fruit. Earwigs are nocturnal in their habits, and during 

 the day take shelter among fallen leaves, under stones, sacking, or 

 boards, etc., lying on the ground, and may even burrow into the soil 

 itself. 



In the control of the earwig, a great deal can be done by what may 

 be called clean gardening that is, the removal of all places likely to 

 shelter the insect above ground during the day. Another important 

 means is systematic trapping, one of the simplest methods being to place 

 crumpled newspapers on the ground at nightfall, in which many of the 

 insects will seek shelter, the papers being collected and burned next day. 

 But the best method is the use of the following poison bait: With 121b. 

 of bran mix 6 quarts of water, to which has been added 5oz. of glycerine 

 and 6oz. of sodium fluoride; to this mash add 4lb. of treacle, taking 

 care to thoroughly mix the whole. 



This bait is spread at nightfall in places frequented by earwigs, and 

 should be repeated regularly, especially after wet weather. It is obvious, 

 if satisfactory results are to be secured, that there should be a co-opera- 

 tive campaign organised among the residents of an earwig-infected 

 district. 



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