December, '21] moznette: mango scale control 469 



4. Dr\' dusting sulphur when charged with nicotine sulphate 40% 

 in the form of Black Leaf 40 and applied to avocado foliage was 

 readily removed by succeeding heavy dews and light rains after 

 application. The incorporation of liquid nicotine sulphate 40% 

 caused an aggregation of the sulphur particles and a wettable sulphur. 



5. Liquid lime sulphur solution when com.bined with nicotine sulphate 

 40% solution proved to be the most satisfactory^ combination used 

 in combatting the red spiders, leaf thrips and leaf hoppers and 

 remained effective against the red spiders over as long a period as 

 did the lime sulphur solution applied alone. 



6. Where a grower has a medium, sized grove of avocados, which is 

 usually the case up to the present time, and where a number of 

 insects occur, spraying would be the more effective and cheaper 

 method considering the price of sulphur and nicotine sulphate 

 in the dust form as compared with the same in the liquid form. 



CONTROL OF TWO SCALE INSECTS OF THE MANGO' 



By G. F. Moznette, U. S. Bureau oj Entomology, Miami, Florida 



There are a number of scale insects which attack the mango in Florida, 

 but two found to be the most injurious up to the present time and more 

 generally distributed are the Tessellated Scale, Eucalymnatus tessellatus 

 Sign, and the Mango Shield Scale, Coccus acmninatus Sign. These 

 two scale insects are readily recognized in the field by the difference in 

 shape and color. The Tessellated Scale is oval in shape, but broadly 

 rounded posteriorly. It is of a dark brown in color, with a decidedly 

 mosaic appearance on the upper surface. The Mango Shield Scale is 

 yellowish green, and in shape it is deltoid, bluntly pointed in front and 

 broadly rounded posteriorly. It is very thin and flat and irregularly 

 marked with black. 



Both of these scale insects infest the lower surface of the foliage, 

 usually clustered along both sides of the midribs. When very numerous 

 they may also be found along the lateral veins and the interstices. 

 The scales reproduce continuously throughout the year, the generations 

 overlapping considerably so that at any time one may find the scales in 

 almost any stage of development. During the spring months the 

 scales move from the older leaves onto the new growth of foliage. Usually 

 these are the crawlers, but even the older scales often leave their 

 feeding grounds and wander to the new growth. 



'Published by permission of the Secretary of Agriculture. 



