Title: Annals of applied biology
Identifier: annalsofappliedb09asso (find matches)
Year: 1922 (1920s)
Authors: Association of Applied Biologists; Association of Economic Biologists
Subjects: Biology, Economic; Biochemistry
Publisher: [Wellesbourne, Warwick, etc. Association of Applied Biologists [etc. ]]
Contributing Library: MBLWHOI Library
Digitizing Sponsor: MBLWHOI Library

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Damage by larvae. (Figs. 2 and 3.) Though larvae of Sitona are to be found very commonly damaging roots of clover in the field it is not easy to determine to which species they belong, as at present there is no comparative description of the larvae published, and also when dug up from the field they are difficult to rear. The injury was therefore determined

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Fig. 2. Plant of red clover with root damaged by larvae of S. hispidula. A and B = holes at base of plant bored by larvae and causing death of shoots A 1 and B 1. C = holes bored on root. D = side rootlets eaten by larvae. E = root nodule eaten by larva.
Fig. 3. young plant of red clover almost bitten through at F by larvae of S. hispidula.

by breeding experiments. Eggs were introduced into pots of clover covered with muslin (10, p. 283, Plate XVIII, fig. B). In unifected pots the clover remained strong and healthy, but in pots infected with eggs of S. hispidula much of the colver died before the larvae had ceased feeding owing to the damage they had inflicted upon the roots and the plants that survived were thin and weak. The larvae bored deep holes all over the main root and when half grown they were sometimes found entirely buried in the root. The portion of the root just below the crown of the plant was frequently chosen for attack with the result that the shoot immediately above the damaged area died. In all the larger plants so affected the outer shoots were dead from this reason whilst in small plants the whole root was sometimes bitten through at this point. The surface of the main roots were also gnawed in patches, the side rootlets were bitten off and the nodules destroyed. The gnawed portions of the root decayed and turned brown.
Field observations indicate that the greater part of the injury is done in June and July when the larvae are most abundant and plants of colver with the roots injured as described above have been dug up from the fields in these months and from the larvae that were found beside them adults of S. hispidula were duly reared.

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