511 



Investigations are still in progress concerning the habits of rice pests. 

 The most common of these are the moths, Schoenobius incerlellus, Wlk., 

 and Cwa/)/w/oc;'ocjsm(?(^iMa/?s, Gn., which hibernate in the stubble at its 

 base. The pupae are very resistant and develop equally well in the 

 dry stubble or when exposed to extremes of temperature or prolonged 

 humidity. They are apparently not attacked by other insects. 



Annual Report of the Department of Agriculture for the Year 1920. 



Mauritius, 1921, 19 pp. 



In this report for the year 1920 an important decrease has been 

 recorded in Mauritius of Lachnosterna {Phytalus) smithi [R.A.E., 

 A, ix, 145]. The special export tax was levied on all sugars leaving 

 the Colony to defray the expenses of campaigns against this pest, 

 and by this means upwards of /5,000 were available in 1920. 



Oryctes tarandus is reported to be less in evidence in places where it 

 was formerly a serious pest. The parasite, Scolia oryctophaga, imported 

 from Madagascar in 1917, has established itself, except on cultivated 

 lands. Among minor pests, the mango Cecidomyiid fly [Proconfarinia 

 matteiana, Kieff.] has spread over a wider area. 



Plant inspection was carried out, together with fumigation and 

 treatment of consignments of plants. 



Gray (G. P.). The Present Status of Lime-sulphur Solution vs. Dry 

 Materials. — Mtlily. Bull. Cat. Dept. Agric, Sacramento, x, nos. 

 5-6, May-June 1921, pp. 177-182. 



The author, who was among the first to publish an analysis of lime- 

 sulphur in powder form as an orchard spray, is still of the opinion 

 that when dissolved it forms a spray similar to the usual lime-sulphur 

 solution, provided equivalent quantities are used. 



The first firm to place this powder on the market claimed that the 

 amount of the new powder dissolved in water would only need to 

 contain about half the active ingredients of the old lime-sulphur 

 solution, as certain organic material in the dry compound prolonged the 

 effectiveness of the spray, thereby reducing the amount of sulphur 

 required. These views were not accepted, and fruit growers were 

 advised to continue to use the old spray until experiments proved the 

 new one more efficient. The same attitude was taken in respect of 

 compounds of soda and sulphur and the barium-sulphur compounds, 

 for which similar claims had been made. 



The points to be decided are whether satisfactory results can be 

 obtained by following the manufacturer's directions, and whether the 

 components of the dry compounds are twice as effective as the same 

 substance in the commercial lime-sulphur solution. 



Owing to the war, few comprehensive experiments have been carried 

 out. The published data on the first question are contradictory, partly 

 owing to the different climates and types of insects and fungi experi- 

 mented upon, and to uncertainty as to the composition of the materials 

 used. Data on the second question are of doubtful value if the com- 

 position of the materials used is assumed to be, as stated on the label or 

 by analysis, other than those actually used. Owing to imperfect 

 regulatory laws, the composition of materials in experiments may 

 differ from those guaranteed on the labels. Instances are given when 

 material supplied for experiments was superior to the average 

 commercial product. 



