INSECTS OF THE CITRUS FRUITS 313 



Thrip. — Besides the scale insects several others are inju- 

 rious. The orange thrip is often troublesome and is found 

 principally in the flowers of the citrus fruit. The presence 

 of the thrip is usually first detected by the distorted and 

 irregular growth of young leaves. 



The thrip injures the fruit by producing irregular scars 

 around the stem and at other places over the surface. The 

 damage done to the fruit does not injure the edible qualities, 

 but it reduces the sale and places it in an inferior grade. 



The most effective remedy for the thrip recommended 

 by the United States Department of Agriculture is 2| quarts 

 of commercial lime sulphur at 22° Baume plus 3| fluid- 

 ounces of a 40 per cent. Black Leaf extract to 30 gallons of 

 water. This material should be sprayed on the trees with a 

 force of 175 or 200 pounds pressure. 



Red Spider. — There are two species of red spider injurious 

 to the citrus fruit. They are found throughout the citrus 

 regions both in Florida and in California. 



The red spider is a small red insect which often becomes 

 so abundant on a leaf as to give a reddish color to it. The 

 best remedy for the red spider is sulphur. It is used in 

 either the dry form or in the form of lime sulphur solution. 

 When it is used dry the sulphur is dusted on the plant, 

 usually when the foliage is a little damp. When lime sulphur 

 is used the commercial product is diluted 1 gallon to 35 

 gallons of water. The lime sulphur is becoming more popular 

 and its cost is much less than fumigation. 



Whiteflies. — The whiteflies are serious pests to the citrus 

 industry especially in Florida. In fact they are perhaps 

 among the most destructive insect pests in that region. 

 There are eight different species which may be found on 

 citrus fruit in Florida. The common citrus whitefly, the 

 woolly whitefly and the cloudy-winged whitefly are the 

 three most important species, while the mulberry whitefly, 

 guava whitefly, sweet potato whitefly, bay whitefly and the 

 flocculent whitefly are found in this region but are of minor 

 importance. 



The whiteflies are small insects, usually white in color, 

 although some species have blotches on their wings which 



