202 



The burrows are not always easy to locate, but as a rule exuding frass 

 'or moisture reveals them. The caterpillar may be removed with a 

 knife and the place painted with coal-tar creosote, or white lead. 

 Adhesive material will trap many ovipositing females. Penetrating 

 oily or poisonous liquids kill many borers in their shallow mines, 

 as many as 85 per cent, being destroyed by kerosene emulsion and the 

 standard emulsified oil sprays, with small additions of sodium arsenate. 

 Nicotine sulphate washes are less effective, but some coal-tar products 

 destroyed 90 per cent, of the borers without injuring the bark. 



WiLDERMUTH (V. L.) & Gates (F. H.). Clover Stem-borer as an 

 Alfalfa Pest.— C7.5. Dept. Agric, Washington, D.C., Bull. 889, 

 25th October 1920, 25 pp., 6 figs., 1 plate. [Received 22nd 

 February 1921.] 



The clover stem-borer, Languria mozardi, Latr., is often referred to 

 in literature as a pest of red and mammoth clovers, the larvae sub- 

 sisting upon the pith of the stems. During recent years, especially 

 in the south-western semi-arid and irrigated regions, the larvae of this 

 Erotylid beetle have become an important pest of lucerne {Medicago 

 sativa) ; they feed on the centre of the stem, causing it to become 

 woody and liable to break off. 



The distribution of L. mozardi covers practically all the United States, 

 as well as parts of Canada and Northern Mexico. Besides clover and 

 lucerne, there are numerous other food- plants, many being Compositae. 

 A number of these are weeds, the destruction of which wall aid in 

 checking the pest. 



The average length of the complete life-cycle in Arizona is about 

 60 days ; this period is noticeably less during the first generation, 

 owing to the shorter time between emergence and pairing, in 

 spite of the fact that the egg-stage is longer than in July and August. 

 A minimum life-cycle of 50 days has been noted, and a maximum 

 of 70. The observed average duration of the egg-stage was 3'8 days, 

 of the larval stage 34-5 days, and of the pupal stage 9 days. 



There are three distinct generations in the south-western States. 

 The first begins in early May, the second about mid-Juh^ and the third 

 in autumn, though in the field the last two are not separable. In the 

 eastern United States there is only one annual generation, the hibernat- 

 ing beetles appearing in late April or early May and the new adults 

 in August. Hibernation occurs in almost any place, such as fence rows, 

 ditch banks, etc., providing shelter against freezing temperatures. 

 A few records show that this species can occasionally hibernate in 

 the larval stage. 



Natural enemies comprise toads, birds, and the Hymenopterous 

 parasites, Hahrocytus langiiriae, Ashm., which often infests 30 per cent, 

 of the larvae, Heterospilus sp., and Eurytonia sp. The value of the 

 last-mentioned is questionable, as it is both primary and secondary, 

 having been also taken from the larvae of H. languriae. This also 

 applies to Eupelmiis allyni, French. 



The injury to lucerne and red clover can be partly eliminated 

 by destroying sweet clover, weeds and waste lucerne, and by cutting 

 the hay crop before the larvae have developed. Crop rotation, and 

 clean farming, such as burning rubbish, etc., will also check this 

 pest. It is unable to develop where pasturing is practised 

 continuously. 



