ORANGE INSECTS. The insects which affect the orange. also. as a rule, affect the lemon and other trees of the genus Citrus. The most important and injurious are the scale insects of the family Coecid:c. which attack the leaves, twigs. branches, and trunk. The long scale (Ifyti laspis Glorcri) and the purple scale (Ilyalaspis citricola) were for a long time the principal in sect enemies of the orange groves in Florida. but the Florida red scale (As•pidiotu.s /ices) and the chaff scale (Parlatoria peryandei) have become numerous and injurious. In Louisiana the chaff scale has been the principal enemy. although the purple scale has done some damage. The orange hionaspis (('hionaRpis citri) also occurs alumn a ntly in this State as well as in Mexico and the 'st Indies. In California none of these species are noted as pests in the orange groves. although the purple scale and the long scale have been accidentally introduced into sonic localities dur ing the past few years. The principal California scales are the California red scale (.1sphliotus eitrieola), the white or fluted scale (feerya Pur•chasi). and the black scale (Lecanium olor). The white or fluted scale has been prac tically exterminated by the introduction of the Australian ladybird ( rardinalis—see LADYBIRD), and the black scale is more of a pest to the olive orchards than to the groves. The California red scale is therefore the only serious scale-insect enemy to the citrus trees of California. and is kept in check by fumigation with hydrocyanic acid gas, and by spraying with the kerosene distillate emulsion. The soft scale (Lcceniuni hesperidum), the hemispherical scale (Leranium hemispherrieum). the Florida wax scale (Ceroplastes Floridensis), and the barnacle scale (Ocrop/aRtcs eerriprdiformi.5). as well as the common mealy-hug (Dartylopins eitril. are also found in orange groves. but seldom do any great damage. See SCALE INSECT.
A rather serious pest in Florida. and to a lesser extent in Louisiana. is the white fly (A leyrodcg citri) which sometimes swarms upon the leaves of citrus fruits. stopping the pores and extract ing the sap, and which through its saccharine excretion is also the nidus for the spores of a black smut-fungus which further damages both the health and appearance of the trees. and fruit. A mite enemy of the orange injures the fruit to sonic extent, and is especially harmful to the salable value of the fruit. This is Phytoptus
oleirorus, called the 'rust mite of the orange and the 'silver mite' of the lemon, since it pro duces a rusty appearance on orange fruit and a silvery appearance on lemons. The sovereign remedy against these mites is flowers of sulphur added to kerosene emulsion spray. Another mite which occurs upon oranges, and which is closely allied to the so-called 'red spider' of green houses, is the six-spotted mite s(x maeulatus). It feeds mainly on the under sides of the leaves, and it is also readily controlled by the use of sulphur• in sonic form or another. (See MITE.) Some damage is occasionally done to orange trees by termites or so-called white ants,. but usually because of some prior damage.
The leaves are injured by the orange aphis (Siphonophora citrifolia ), and by several suck ing bugs, such as the green soldier bug (Yezar•a hilaris) and the thick-thighed metapode (Rcte hoe1iu•s fentoratus). A number of caterpillars feed upon the leaves, the most conspicuous of which is the larva of Papilio cresphontes, some times known as the 'orange dog.' The saddle back caterpillar (larva of Ern pretia sthnuleal, and the bagworm (larva of rhketh-us and several other less prominent lepidopterous larva eat the leaves to a greater or lesser extent, and there are several leaf-rollers which also damage the foliage. The cotton-stainer (q.v.) or red-bug (Dysdereus saturdlus) punctures the fruit: as does also the leaf-folded bug ( Lep/0 glosses phyllopus). A very serious enemy of the orange in Mexico. and one the advent of which is greatly feared by the oranee-growers of th United States. is the Morelos orange worm or fruit-fly, the larva of Trypeta ludens. Here the fly lays her eggs upon the skin of the young orange. and the maggots which batch from these eggs penetrate the pulp and ruin the fruit. Nearly all of the species just mentioned occur in Mexico and the West Indies, and several of them are found in the orange groves in ranean regions. In South Africa and Australia the orange has a different insect fauna, but the species are allied to those in America and repre sent practically the same groups.
Consult: Iliddlard. lascets of the Orange (De partment of Agriculture. Washington, Marlatt. "The Seale Insect and Enemies of Citrus Trees." in Yearbook, D• partment of Agri culture for 1900 (Washington. 1901).