182 INSECTS AFFECTING CITRUS FRUITS 



Below, the wings are yellow, with blue spots on the hind pair. 

 Control. Hand-pick the caterpillars and pupae. 

 Orange Aphis. This is a black or brownish aphid (Siphono- 

 phora sp.) with yellowish legs. It sucks the sap from the twigs of 

 the orange. Both winged and wingless forms may be seen on the 

 trees at the same time, the winged form migrating to other trees. 

 The life history of the orange aphis agrees in general with that of 

 other aphids. 



Control. A spray of strong soapsuds or tobacco extract, with 

 soap added, is generally sufficient to control this pest. It is 

 attacked by predaceous and parasitic insects. 



Orange Thrips. Of the various species of thrips which work 

 on the orange, this (Euthrips citri Moul.) appears 

 to be the most injurious, for if it does not render 

 the fruit unmarketable (Fig. 201), it at least 

 obliges grocers to classify it as an inferior grade. 

 In certain regions in California it is proving 

 an injurious pest. Various species of thrips 

 may be observed about the blossoms of orange 

 FIQ. 202. The cot- trees. They are blackish or yellowish insects 



ton stainer. . . 



which move rapidly. 



Control. Spraying is the most effective method of controlling 

 these insects, and the following is recommended by the United 

 States Bureau of Entomology : 



Commercial lime sulfur, 2^ gallons; black leaf extract, 2 gallons of 2 ^4 

 per cent or 14 fluid ounces of 40 per cent; water, 200 gallons. 



Possibly three applications may be necessary at intervals of 

 about ten days. The spray should be applied forcibly. 



The Rust Mite. The rust often observed on the fruit of the 

 orange is caused by the activities of a whitish mite (Phytoptus sp.) 

 which is frequently found in large numbers on the skin. 



Control. A strong soap solution is recommended for the ex- 

 termination of this pest. 



The Cotton Stainer (Dysdercus suturellus H. Schif.). This 

 bug is not only a bad pest of cotton, but it also sometimes seriously 

 injures the fruit of the orange by sucking the juice. As a result of 

 its work the fruit may decay and fall. When adult (Fig. 202) its 

 ground color is black, with red anterior markings. The margins 

 of the body are pale yellow, and two white lines cross on the back 

 when the wings are folded. It is bright red below. The eggs are 



