342 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 14 



of various insect pests, more so, than the decidous fruits growing in the 

 temperate clime. The insects attacking the avocado in Florida are 

 subject to varying changes of climatic conditions as far as their activi- 

 ties are concerned, which possibly would not attack the avocado grow- 

 ing in a more northern latitude as California. While some of the in- 

 sects which attack the avocado in Florida may have been introduced, 

 others ma}^ be insects which have always been present on native vege- 

 tation and have adapted themselves to the avocado as a host. 



During the winter season in Florida, the avocado is dormant and the 

 precipitation is greatly decreased from what it is during the summer. 

 At this time of year various enemies attack the avocado which thrive 

 imder conditions of little rainfall and low humidity. One of the ene 

 mies which attacks the avocado at this time is the Avocado Red Spider 

 {Tetranyclius yothersi, McG.). In appearance this spider does not dif- 

 fer materially from the other species of Tetranychus which attack va- 

 rious other fruits. Unlike other red spiders, however, it confines its 

 depredations to the upper surface of the foliage. Orchards heavily 

 infested with red spiders appear in a short time as if scorched by fire. 

 The foliage turns brown and frequently there is a heavy shedding as 

 a result of their attacks. 



Another enemy of this fruit during the winter is the so called green- 

 house thrips of the north {Heliothrips hemorrhoidaHs Bouche') which 

 attacks the avocado in the opeii. Like the red spider it confines its 

 work to the upper surface of the foliage. Besides producing the pale 

 colored areas to the foliage which later assume a brown color and ap- 

 pear scorched, the foliage also becomes thickly covered with minute 

 drops of blackish fluid voided by the thrips. Eventually the foliage 

 drops prematurely as in the case of the red spider. 



The loss generally sustained through an infestation of the red spider 

 and leaf thrips, results in injury to the starch laden foliage of the avo- 

 cado during the winter. By premature defoliation a set back usually 

 results to the trees the following spring in their activities to set a full 

 crop of fruit. The over wintering foliage should remain on the trees 

 for some time after the blossoming period when new foliage is produced 

 to take its place. 



These two pests can be controlled effectively on the avoca- 

 do by spraying wnth liquid lime sulphur 1 to 50 with the addition of nicotine 

 sulphate 40% at the rate of 1 to 900' to the diluted lime sulphur with 

 cut injury. The powdered lime sulphur has Ijeen found to work satis 

 factorily using 2 pounds to 50 gallons of water incori3orating the nico- 

 tine sulphate 40% as is used in connection with the liquid lime sulphur 

 solution. <^ 



