December, '17] VAN ZWALUWENBURG: COFFEE INSECTS 515 



Coffee Leaf Weevil 



A weevil ("vaquilla") belonging to the genus Lachnopus is of pri- 

 mary importance in many plantations. It is not known to occur at 

 elevations less than 300 meters. 



This weevil is most abundant during April and May. It is at this 

 time that the adult does enormous damage by feeding not only upon 

 the leaves, but also upon the blossom buds and the newly set berries 

 which are to produce the crop. The life history study of this insect 

 has so far been unsuccessful in the warm climate of the coast. 



Field observations indicate that the weevil has a one-year life 

 cycle. The eggs are laid in flat masses of fifty or more between two 

 overlapped leaves; on hatching, the larvae enter the ground where 

 they feed on the roots. The greater damage is that caused by the 

 adult. The weevils feed upon Vitex divaricata in addition to coffee. 

 A Chalcid has been bred from what appeared to be the egg cluster of 

 this insect. Jarring the trees and hand picking during the months of 

 adult abundance have been recommended, but have not yet been tried 

 on a large scale. 



Coffee-Shade Ant 



In some districts the most serious pest of coffee is the "hormiguilla,'^ 

 an ant which is primarily a pest of coffee-shade, but too often attacks 

 the coffee trees also. This insect (Myrmelachista amhigua Forel subsp. 

 ramulorum Wheeler) eats out irregular longitudinal tunnels in which 

 it rears its brood and cultivates colonies of two species of soft scales. 

 When the host tree is coffee, the guest scale is a Pseudococcus; in most 

 of the trees shading the coffee the guest is a fleshy, pink scale, represent- 

 ing a new species of Coccus. In coffee the tunnels are made in the new 

 growth; this not only lessens the vitality of the plant, but also weakens 

 the branches so that many are broken when the pickers bend them over 

 to gather the berries. 



Numerous poisoned baits and sirups have been tried without suc- 

 cess. The only method promising relief consists in felling and burning 

 all infested growth, planting temporary shade such as banana, in 

 which the ant will not colonize, and after several months replanting 

 permanent shade trees. By this means a 75-acre area has to all ap- 

 pearances been kept entirely free from the ant for about seven years. 

 This method is very expensive and is of doubtful permanent value, 

 for the danger of reinfestation from without the cleared area is always 

 present. 



A small yellow, very vicious ant known as the "albayarde" (Was- 

 mannia auropunctata Roger) is reported to occasionally kill and dis- 

 place colonies of the "hormiguilla." However this ant's pugnacity is. 



