384 



The list includes Icerya purchasi, Mask.,, taken on a cultivated 

 species of Rosa, not yet known in western or equatorial Africa ; 

 Or'hezia insignis, Dougl., on Coffea arabica, being abundant on the 

 leaves, attacking for preference the terminal shoot and probably 

 encouraging the development of Capnodium caffeae ; it has not yet 

 been observed in French territory in Africa ; Pseudococcus citri, 

 Risso, taken on roots and fruits of Theobroma cacao ; Ceroplastes 

 sp., abundant on the branches of Coffea arabica ; Vinsonia stelUfera, 

 Green, on leaves of Citrus sp., but not yet known to occur in 

 Africa ; Saissetia (Lecaninm) nigra. Nietn. , abundant on leaves of 

 Hevea guyanensis, but apparently not very harmful ; Coccus (L.) 

 viridis, Green, on leaves of Coffea liberica, is a dangerous pest 

 and should be watched, though fortunately, its most important 

 natural enemy, the fungus Cephalosporimn lecanii, also occurs in 

 San Thome ; Aukicaspis penfagona, Targ. , abundant on Carica papaya 

 and on Hevea guyanensis, but not yejs known to occur on the coast 

 of the mainland ; Pseudaonidia trilobitiformis, Green, taken on 

 Theobroma cacao ; Aspidiotiis palmae, Morg. & Ckll., abundant on 

 leaves of Carica papaya and Artocarpus incisa and less common on 

 those of Theobroma cacao, Persea gratissima and Citrus sp. ; Selenaspidus 

 articulatus, Morg., on Theobroma cacao and other plants ; Morganella 

 7naskelli, Ckll., on Persea gratissima, in company with Aulacaspis 

 pentagona ; Lepidosaphes heckii, Newm. {cifricola, Pack.) on Citrus 

 spp. ; and Ischnaspis filiformis. Dougl., found rarely on leaves of 

 Coffea liberica. 



Weldon (G. p.). Pear Growing in California.— M^^Zy. Bull. Gal. State 

 Commiss. Hortic, Sacramento, vii, no. 5, May 1918, pp. 371-407, 

 figs. 165-186. 



Among the numerous insect pests of pear trees dealt with in this 

 bulletin are Polycaon confertus (branch and twng borer), which oviposits 

 on the twigs of pear and other trees. The larvae bore into the twigs, 

 frequently causing them to break. This pest is usually troublesome 

 in the neighbourhood of brush piles, in which it hibernates and breeds ; 

 consequently brush piles and orchard prunings should be cleared 

 up. Aphis medicaginis usually feeds on leguminous plants, such as 

 sweet and bur clover, etc., but attacks pears when there is a scarcity 

 of its usual food-plants, feeding upon the tender tips of the twigs. 

 Gymnonychus californicus (California pear sawfly) in the larval stage 

 eats circular- shaped holes in the leaves. Eulecanium (Lecanium) 

 cerasorum (cherry or calico scale) is abundant in some localities, but 

 does not generally require artificial control measures. E. (L.) corni 

 is commonly found on pear trees, but its parasite, Comys fusca, 

 generally serves to keep it in check. Borers include Chrysobothris 

 femorata (flat-headed apple-tree borer), which frequently causes the 

 death of injured or weakened trees ; preventive measures include the 

 protection of the trunlcs of young trees by whitewashing, or by tree 

 protectors made of yucca or of heavy paper. Xyleborus xylographus 

 (lesser shot-hole borer) bores small holes at the base of buds or into 

 the heart of branches. All dead wood and prunings should be removed 

 to prevent hibernation of this species and of Scolytus {Eccoptogaster) 

 rugulosus (shot-hole borer or fruit-tree bark-beetle), which has similar 



