PINEAPPLE PESTS— PLANT LICE 



1687 



is not too severe the plant may produce 

 a fruit, but it is usually of poor quality 

 and ripens prematurely. 



Cause 



It is often impossible to tell just how 

 the trouble starts, as it may break out 

 simultaneously in widely separated places. 

 It can probably exist in the soil under 

 some conditions for long periods, and it 

 may be carried from plant to plant by 

 ants and other insects. Its presence is 

 usually due to faulty soil conditions, 

 though Australian investigators claim 

 that it also occurs where a field is cropped 

 too long, and by adhering to one source 

 for supply of plants, as well as poor cul- 

 tivation and fertilization. 



Bemedies 



The first precaution to be taken is one 

 of prevention. Never plant a slip that 

 could possibly be already diseased. Sec- 

 ond, if the disease should appear, pull 

 out all plants affected, burn them on the 

 spot, or cover with quicklime; also cover 

 the soil with lime and leave exposed to 

 the sun for a few weeks, stirring it from 

 time to time. After a month or six weeks 

 strong, healthy plants may be reset in the 

 vacant places. Third, keep the plants 

 growing vigorously and the soil in the 

 best possible physical condition. 



PINEAPPLE PESTS 

 Mealy Bug 



This pest is easily controlled by sprink- 

 ling tobacco dust in the crown. The 

 tobacco dust acts also as a stimulant to 

 the plant. 



Pineapple Scale 



Diaspis bromeliae Kern. 

 General Appearance 



The outer shells or scales of the females 

 are thin, circular and nearly pure white 

 in color, with exuviae yellow. The bodies 

 proper are yellow or orange, sometimes 

 with blue or purple tints. 



Life History 



The females usually attack the leaves 

 into which they burrow and may become 

 almost entirely hidden under the epi- 

 dermis. The fruit is also infested. 



Control 



Spraying when the pest occurs in the 

 field with kerosene emulsion and resin 

 wash offers effectual control. 



E. O. EssiG 



Plant Lice 

 ♦NATURAL ENEMIES OF PLANT LICE 



Apbis Lion, or Green Lace Wing 



Chrysopa californica Coq. 

 One of the most common insect pred- 

 ators, working on all sorts of soft-bodied 

 species, is the common green lacewing, 

 called aphis lion, because of its destruc- 

 tiveness to all plant lice. The eggs, lar- 

 vae, pupae and adults are to be found 

 everywhere in the fields, woods and or- 

 chards. In the citrus orchards of South- 

 ern California they are very abundant 

 and play an important part in the con- 

 trol of many bad pests, but more impor- 

 tant in keeping down the aphids. 



Eggs 

 The eggs are very small, pearly white 

 in color, oblong in shape with the base 

 drawn out to connect with a fine hair or 

 pedestal which supports it nearly half an 

 inch above the surface to which the hair 

 is attached. The egg itself is not more 

 than an eighth of an inch in length. The 

 adult insect has no doubt employed the 

 method of placing her eggs on long stocks 

 for the purpose of putting them out ot 

 the reach of other crawling insects which 

 would otherwise devour them. 



Larva 



When first hatched the larva is of 

 course very small, but grows rapidly. 

 When first born they vary from a light 

 yellow to a gray color. As soon as it 

 leaves the egg the search for food is be- 

 gun and apparently there are few insects 

 which escape its appetite. At first only 

 the very youngest plant lice are devoured, 

 but it is not long before insects twice 

 and sometimes three times as large as the 

 lacewing are destroyed. The full-grown 

 larvae varies from half to nearly an inch 

 in length, is bright yellow with dark red 

 markings. The head is equipped with a' 

 large pair of mandibles, grooved on the 

 inner side, curved like a sickle and 



•E. O. Essig. Cal. Com. Hort. Vol. 1, No. 10 



