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TWENTY-EIGHTH FRUIT-GROWERS' CONVENTION. 



that the bad effect from the work of the thrips is seen some years as early 

 as December. In following up my examination this year I found that 

 the spotting kept up into February. Some of the oranges would spot as 

 late as that, or until the fruit gets so ripe that the insects fail to work 

 very much, and then they went onto the lemons. In our county we 

 have one man whose business it is to follow up the thrips and note 

 every change. For instance, one of his particular instructions is to 

 watch and see when the thrips first go onto the new fruit. Further 

 than that, I will say that the thrips do not affect all orchards alike. 

 For instance, when I first went to find the work of the thrips, I was told 

 that the worst spotted oranges came from a certain orchard. The fruit of 

 that orchard was all picked. The next orchard was pretty nearly picked. 

 An,d I went there to look for them, but I could not find either the spots 

 or the thrips. So my idea is, if you want to know the proper time to 

 spray your oranges to avoid damage by the thrips, have an inspection 

 made, and when you find the thrips at work then is the time to spray. 



MR. SMITH. I should like to ask Professor Cook whether he has 

 noticed two kinds of thrips — one of them bright on the thorax and the 

 other almost entirely dark? Those that are bright on the thorax hop 

 away. Are very hard to catch. Have you noticed that kind? 



. PROFESSOR COOK. Yes, nearly all hop. They do not hop so 

 much when they get more fully developed. In the larval state they 

 are great hoppers. And there is a black thrips, but that is not the one 

 that works here. This is a yellow thrips. 



MR. SMITH. You think it is all one variety? 



PROFESSOR COOK. I think those that I have seen working on 

 the oranges here — the yellow — are. We feel very certain of four 

 different kinds, but there is only one that works on oranges, so far as I 

 know. And that may be tritici. I am not at all certain it is not. 

 They are very much alike — very little difference, indeed, between those 

 two species. 



PROFESSOR PAINE. I can give you my observations on that 

 point. They say they are upon lemons, and of course it is so. I have 

 not noticed them on my lemons, but at one time I concluded that they 

 were infesting the Navel orange, because of the housing it afforded 

 them. At the same time that I saw they were abundant on the Navel 

 orange I saw that they had crowded into the navel cavity, which seemed 

 to shelter them both from its position and the overhanging way of the 

 orange; and I found them very abundant, and early in the morning 

 when it would be cold and damp they would be nearest that navel. 

 Later in the day they would spread farther from it. And at the same 

 time I would note my seedlings, Valencia Lates, St. Michaels, and 

 Mediterranean Sweets; and at no time during the day did I find any 

 thrips at all there. Later I have seen a few on some of those oranges, 

 but very few indeed. I never saw any on my lemons. 



