Insects that Attack Vegetables' 



As there are more than loo insects 

 that from time to time are found 

 doing considerable damage to 

 vegetables it is impossible to discuss 

 these all in one paper. I shall, there- 

 fore, devote my attention only to a few 

 of the most troublesome, viz., cutworms, 

 flea-beetles, asparagus beetles, the strip- 

 ed cucumber beetle, root maggots, cab- 

 bage worm, wire worms, and aphids. A 

 good account of most of these and of 

 many other insects is to be found 'n 

 "Inserts Injurious to Vegetables," pub- 

 lished by Orange Judd Co., and costing 

 $1.50. (This may be purchased through 

 The Canadian Horticulturist — Editor.) 

 Every vegetable grower should have this 

 book, and also Bulletin No. 52 from the 

 Department of Agriculture, Ottawa, and 

 Bulletin No. 171 from the Department 

 of .'Vgriculture, Toronto. The latter bul- 

 letin contains also an up-to-date account 

 of the diseases of vegetables with means 

 of prevention. 



There are certain farm practices that 

 are employed by many but not by all 

 vegetable growers, and that are import- 

 ant in keeping not only insects but what 

 is also equally as important, plant dis- 

 eases, in check. 



DESTRUCTION OF RUBBISH 



(i) Destroy all remnants of crops and 

 all rubbish so far as possible each fall. 

 This should be done by gathering and 

 burning, and not by ploughing down as 

 the latter method would not destroy fun- 

 gus or other diseases. By burning the 

 vines, leaves and other remnants of 

 plants, we not only destroy any insects, 

 like* borers and miners that may be con- 

 cealed inside the leaves, stems or roots, 

 and the eggs that are laid by plant lice 

 and other insects on the plants, but we 

 also remove the natural hiding. places for 

 large numbers. Keeping fence corners 

 mowed and clean, and having as little 

 brush as possible on or around the field 

 or garden will also assist in the same 

 way. 



FALL PLOUGHING 



(2) The turning over of the soil in au- 

 tumn buries deeply numerous insects that 

 pass the winter in the egg or pupal stage 

 on or near the surface of the ground. 

 Many of these will be unable to escape. 

 Again many other insects, such as wire- 

 worms and white grubs, are by this 

 means turned up to the sun, rain and 

 frost, and these, along with the stirring 

 of the soil, destroy countless numbers. 

 Furthermore, thorough working of the 

 ground in spring supplements this fall 

 ploughing and destroys its quota. 



(3) It is but natural that most species 



•An extract from an address delivered at the 

 recent convention in London, Ont., of the On- 

 tario Vegetable Growers' Association. 



L. Caesar, B.S.A., O.A.C., Guelph, Ont. 



of insects should pass the winter at or 

 near the place where they found abund- 

 ance of food the previous year, and that 

 they should search for it in the same 

 place the next season. Some insects, in 

 fact, are without wings and can only 

 move from place to place slowly. 



Keeping these things in mind, it fol- 

 lows that we should not plant the same 

 kind of crop, or another crop that is 

 attacked by the same kind of insects, 

 two years in succession in the same 

 place, but should replace it by a crop of 

 a totally different kind. This is also 

 better for the soil and so for the crop 

 itself, quite apart from insects and plant 

 diseases ; because one kind of plant takes 

 one substance out of the soil, while ano- 

 ther takes another ; again one crop is a 

 deep feeder, sending its roots far down, 

 while another feeds near the surface. By 

 rotating crops we do much to prevent 

 the rapid exhaustion of the food supply. 

 There may, of course, be an occasional 

 exception to this rule, but such excep- 

 tions are rare. 



(4) The richer the soil is kept and the 

 better cultivated to preserve moisture, 

 the more thrifty the plants will be and 

 the better able to withstand insect 

 attacks. 



THE IN8EOT8 



Just as with anything else, the more 

 we know about insects the more intelli- 

 gently and economically we shall be able 

 to deal with them. From this standpoint 

 the teaching of Nature Study in our high 

 and public schools should give the rising 

 generation an advantage over the 

 present. 



There are, however, a few very impor- 

 tant points about insects that we can all 

 readily learn. The first and most im- 

 portant of these is that insects are divid- 

 ed into two great classes — biting insects 

 and sucking insects. The easiest and 

 simplest way for most people to deter- 

 mine to which class any species belongs 

 is to observe whether in feeding the in- 

 sect removes the tissues leaving holes or 

 ragged edges. If so, it is a biting insect. 

 If on the other hand none of the tissues 

 are removed and the feeding causes the 

 leaves or plants to become discolored and 

 sickly the insect is a sucking one. 



It stands to reason that if the part of 

 the plant that a biting insect feeds on is 

 covered with a deadly poison, like arsen- 

 ate of lead or Paris green, the insect will 

 devour this and be killed. On the con- 

 trary sucking insects cannot be killed 

 by any poison of this kind because they 

 insert their sharp beaks through the skin 

 of the plant and suck the juice from 

 within, thus never having any reason 

 for absorbing the poison. Sucking in- 



262 



sects accordingly must be destroyed by 

 being actually hit by some substance that 

 will kill them by coming in contact with 

 fheir body. The best known of such sub- 

 stances in the case of insects attacking 

 vegetables are kerosene emulsion, whale 

 oil soap, tobacco decoctions, pyrethrum 

 powder and common soap suds. To get 

 good results with these mixtures on some 

 kinds of insects it is necessary to apply 

 them with considerable force while the 

 insects are still young and their bodies 

 soft and unprotected by wings or wing 

 covers. insect stages 



Insects during the course of their life 

 history pass through several quite differ- 

 ent stages. In most cases there is the 

 egg, which hatches into the tiny grub 

 or caterpillar or maggot. When this is 

 full grown it in turn changes into the 

 pupa, usually a smooth, brownish cigar- 

 shaped creature ; and after a time from 

 this there comes forth the winged adult 

 which will lay eggs and thus start the 

 same round again. Of these stages, it is, 

 as a rule, only in the second or cater- 

 pillar stage that injury is done. Hence 

 when we see a large green tomato 

 worm disappear, or a horde of cutworms 

 suddenly vanish, we may expect that they 

 have merely entered the ground to pu- 

 pate and that there will be no more 

 damage from them that season. 



A number of biting insects, like grass- 

 hoppers, and many sucking insects, such 

 as leaf-hoppers and leaf bugs, pass 

 thrdugh only three stages : The egg, 

 nymph and adult ; the nymph differing 

 from the adult chiefly by its smaller size 

 and the absence of wings. Such insects 

 feed in both the later stages. With 

 these remarks which, though common- 

 place to many, may yet be new to a num- 

 ber, and therefore useful to them, we 

 shall pass to a consideration of the very 

 destructive insects mentioned in the 

 introductory paragraph. 



{To he continued) 



The Cabbage Worm 



Prof. H. A. Surficc. 



It will not render cabbage unfit for 

 use to apply paris green to it. If you 

 use one-half pound of paris green in fifty 

 gallons of water sprayed on cabbage, 

 . no evil results can possibly ensue. It 

 would be better to apply some soap with 

 it to make it stick. Also, )'ou can use 

 two pounds of arsenate of lead in place 

 of the paris green. This will stick 

 better, and I much prefer it. 



Practically all truck growers now use 

 arsenical poison on cabbage and are 

 satisfied with the results, as it kills the 

 worms, although, of course, it does not 

 kill plant lice, and is not recommended 



