94 Farmers’ Bulletin 1261. 
thrips of the avocado is to be found toward the center of the tree, but 
also on the outer protected branches. It evidently prefers, and multi- 
ples more rapidly in, the sheltered and protected places. The work 
of the thrips may be distinguished from that of the red spider in 
that the surface, in addition to possessing the pale-colored spots 
where the chlorophyll has been extracted by the thrips, also becomes 
thickly covered with minute drops of blackish fluid voided by them 
(fig. 19). Where excessive defoliation takes place, abnormal bloom- 
ing usually occurs the following spring. Where trees obtain a suffi- 
cient amount of water and food of the proper kind, usually less 
trouble is experienced from the red-spider mite. The avocado re- 
quires plenty of water and is a heavy feeder. 
HOW THE RED SPIDER AND THRIPS MAY BE CONTROLLED. 
If red spiders and thrips become active on the avocado while the 
fruit is still on the trees in the early fall and are doing serious’ 
damage, it will be necessary to spray with fish-oil soap at the rate 
of 5 5 pounds to 100 gallons of water, plus 40 per cent nicotine sulphate 
at the rate of 1 part nicotine sulphate to 900 parts of the diluted soap 
solution. By so spraying the red spider and thrips will be held in 
check until after the fruit has been harvested. The soap and nicotine 
spray is only temporarily effective and does not act against the red 
spider over a period of several weeks as does the lime-sulphur spray, 
but as lime-sulphur adheres to the fruit and is difficult to remove, 
the writer recommends the soap while the fruit is still unpicked. 
If the red spiders and thrips become abundant in a young grove 
which has not reached the bearing age, lime-sulphur concentrate 
should be used at the rate of 1 part to 60 parts water, plus 40 per 
cent nicotine sulphate at the rate of 1 part nicotine sulphate to 900 
parts of the spray. If thrips are not present, the nicotine sulphate 
solution should be omitted. In using lime-sulphur solution it is 
advisable to use a strength of 1 gallon of the concentrate to 75 gallons 
of water during winters when the temperature is above the normal 
and when the trees do not attain a thoroughly dormant condition. 
Fish-oil soap and nicotine generally afford only temporary relief 
against the red spiders, and if these mites continue to.work after the 
fruit has been picked, it will be necessary to spray again. During 
the winter after the foliage has hardened no injury from the use of 
lime-sulphur as recommended above has been noted by the writer. 
Where the thrips are not present at this time it will not be necessary 
to use the nicotine-sulphate solution in combination with the lime- 
sulphur. : 
Where an avocado grower contemplates combating white flies and 
scale insects also during the fall or dormant season, application of the | 
