iVoi;. 2, 1920.] Agricultural Gazette of N.S.W. 819 



he should realise that they are the forerunners of the strawberry pest, and 

 apply his treatment then. This can be done by either spraying the trees 

 with arsenate of lead or Paris green, or by spreading an old sheet under the 

 trees in the early morning or late in the afternoon when the beetles are 

 drowsy, and shaking the tree or brushing it with a bush. By this means 

 hundreds of the beetles can be collected in the sheet and subsequently be 

 destroyed. Another preventive measure is the exercise of some care and 

 discrimination when collecting leaves for mulching. If the grower sees that 

 gum trees have been partly defoliated by beetles early in the spring, he may 

 do well to pass that neighbourhood entirely ; otherwise, he should rake very 

 lightly in order to lessen the risk of picking up with the lower decayed 

 matter either the eggs or the tiny young larvse of the beetles. 



Another means of protection of which the grower can avail himself at 

 little cost is the enlistment of the services of useful insects found preying 

 on the pests. Two of these may be described. 



The first is the large metallic blue scolid wasp {Discolia soror), which can 

 be seen flying about the strawberry bed almost anywhere in summer, and 

 which, if watched, will be seen to burrow her way into the soft porous 

 gro«nd to deposit her eggs on the larvae of the beetles. These young wasp 

 larvie when hatched, attech themselves to the grubs, and feed upon them 

 until fully matured. They then roll themselves up in an oval-shaped silken 

 cocoon, and lie in the ground until the warmth of the coming spring causes 

 them to pupate and emerge as wasps again. It is quite a common occurrence 

 to find a grower killing these wasps — sometimes because he has been stung by 

 one when interfering with him — sometimes because, seeing the wasp enter the 

 ground, he has suspected him of being another pest. This wasp can sting, 

 but it is perfectly harmless if left alone, and is really one of the strawberry- 

 growers best friends. 



The second of our friends is a Therevid fly ; it is illustrated on page 817. 

 Hitherto very little has been known of its life history, and therefore it has 

 not been given its place in economic entomology, but I have for two years 

 collaborated in the study of this family, and have found its larva? to be very 

 widespread. This larvte is very voracious, and will attack almost any soft 

 underground larvae ; indeed, such is its habit, that one cannot keep two in 

 one jar for half an hour without running the risk of one sucking the other to 

 death. I have reared the flies in captivity for the last twelve months, 

 feeding them almost exclusively on curl grubs. I found them among the 

 larvffi of the dicky rice last year, and in collecting grubs from among straw- 

 berries this year for food for them I found that there also they were 

 operating pretty freely. I would therefore strongly recommend every grower 

 to make himself acquainted with the appearance of this fly, and whenever he 

 comes across him when killing others to spare his life. These two friendly 

 insect agents can operate all through the season without interfering with the 

 crop in any way, and though they should not be expected to do more than 

 their share of useful work, they may nevertheless assist the grower materially 

 in turning the balance of nature in his favour. 



