Proceedings of the South & East African combined agricultural, cotton, entomological and mycological conference held at Nairobi, August, 1926

Bibliographic data

Monograph

Identifikator:: 1738588467

URN:: urn:nbn:de:zbw-retromon-115043

Document type:: Monograph

Title:: Proceedings of the South & East African combined agricultural, cotton, entomological and mycological conference held at Nairobi, August, 1926

Place of publication:: Nairobi

Publisher:: East African Standard

Year of publication:: 1926

Scope:: VI, 337 Seiten; Ill.

Digitisation:: 2020

Collection:: Economics Books

Usage license:: Get license information via the feedback formular.

Chapter

Document type:: Monograph

Structure type:: Chapter

Title:: Part IV. Etomology & Mycology

Collection:: Economics Books

PART TV. + Oviposition is effected in the following manner. On the selected site the bug in vertical position with head uppermost grips the surface firmly with all its legs, bending the abdomen almost at right angles to the thorax; the ovipositor is extruded, inserted and gradually pressed up to its base into the stem, the bug swaying slowly from side to side during this act. The egg is then extruded and the ovipositor is first gradually and, owing to the considerable pull necessary, finally removed from the stem with a distinct jerk. The whole operation of oviposition occupies 100 seconds. Both adults and nymphs feed on young leaves and terminal buds, producing brown patches on the leaves and ultimate death of the leaves and buds. Secondary growth is thus induced and this in turn is attacked in serious infestations, eventually producing dense bushes on which no crop can be borne. = So far as is known berries are not attacked. Factors FAVOURING Li. MIMETICUS. As indicated earlier in this paper shade and (probably) certain soil conditions favour the presence of the bug. Owing to the fact that the Agricultural Chemist has not yet the facilities necessary for a soil analysis the possible soil factor has not so far been investigated. Mr. FULLER, in thanking Mr. Hargreaves, asked what the nature of the damage was. Mr. HARGREAVES: It kills the young shoots and stimulates secondary growth, causing bunching. The CHAIRMAN (Mr. Fuller): It possibly resembles the effect of ‘‘ frog-hopper >’ on the wattle in South Afriea. From wattle several species of Jassids, also a Capsid, have been reported, and trouble occurs more or less regularly, one insect being in the ascendancy at one time and another at another time. Mr. HARGREAVES, in reply to Mr. Ritchie, stated that the symptoms are similar to the twig infestation of Colletotrichum, and that the effect is very similar to that caused by Antestia. Mr. FULLER asked Mr. Hardenberg to explain something of the ‘“ witchbroom *’ formation in wattle. Mr. HARDENBERG said that he had now more or less come to the conclusion that the insect was not so much to blame. He attributed the damage to the inoculation of a fungus by some insect. The plants were attacked generally at some 6 {t. to 12 ft. above the ground, which is the height at which most of these insects fly. The insects were responsible in some way but he had not really been able to distinguish cause from effect. The CHAIRMAN (Mr. Fuller) said it would seem that it is: simply a disturbance by the insect causing malformation. Mr. RITCHIE said that a species of Lycidocoris (L. modestus) damaging coffee had been reported from the Congo on deeply shaded coffee. Mr. HARGREAVES stated that the presence of deep shade is. the chief factor in the prevalence of Lycidocoris in Uganda. In reply to a question by Mr. Fuller, he said that the bugs suck the juice from the young shoots and leaves, causing spotting; the leaves and terminals eventually die. The damage to the leaves is similar to that caused by Helopeltis on tea. 198

Access restriction

Copyright

fullscreen: Proceedings of the South & East African combined agricultural, cotton, entomological and mycological conference held at Nairobi, August, 1926

Monograph

Chapter

Table of contents

Download

Monograph

Chapter

This page

Image fragment

Citation links

Citation recommendation