538 



McSwixEv (j). Report of the Agricultural Department, Assam, 

 for the year ending 31st March 1921, SIiilioii,s:, 1921, pp. 7-8. 

 [Received 14th September 1921.] 



The pests recorded during the year under review were : — Hispa 

 armigcra (rice Hispid), Leptocorisa varicornis (rice bug), Schoenobiiis 

 incertelliis [bipundifer) (rice stem borer) and Ripcrsia sacchari (mealy 

 bug) on rice. An outbreak of the latter was checked by promptly 

 weeding out affected plants. The use of ropes to dislodge army worms 

 and swarming caterpillars and the spreading of a thin film of kerosene 

 oil on the water in the fields provecl effective. 



Crickets attacking soy beans were destroyed by the use of a termite 

 exterminator. A species of Apion destroyed the flowers and seeds 

 of arhar [Cajamis indiciis]. Diacrisia olliqua, attacking various pulse 

 crops and jute, was controlled by systematic hand-picking and by 

 destruction of the egg-masses. A Chrysomelid, Pagria signata, caused 

 some damage to leaves of cowpeas. The rape crop was again attacked 

 by the mustard Aphid and a sawfly [Athalia proxima]. Against the 

 latter, dusting with sand and ash sprinkled with kerosene [cf. R.A.E., 

 A, vii, 492] proved successful. Other miscellaneous pests were Agrotis 

 ypsilon attacking young seedlings, especially of potatoes and tobacco ; 

 mealy-bugs attacking fruit trees ; a beetle on rhubarb ; and Cantharid 

 beetles injuring various crops, including potatoes. 



Borden (A. D.). A Biological Study of the Red Date-palm Scale, 



Phoenicococcus marlatti. — Jl. Agric. Res., Washington, D.C., xxi, 

 no. 9, 1st August 1921, pp. 659-668, 4 plates. 



Practically all the imported palms (over 10,000) in the Coachella 

 Valley, California, are infested with Phoenicococcus marlatti, Ckll. 

 Although the quarantine act of 1913 affecting the interstate move- 

 ment of infested palms has restricted the distribution of this scale 

 outside infested States, dissemination within the attacked area has 

 only been partly retarded. The most important source of distribu- 

 tion is through the offshoots that become infested from the bole of 

 the parent plant. The accidental carriage of scales by man, birds, 

 wind, etc., is of no great importance. Dispersion by natural migration 

 can only take place during the early stages and then only to different 

 parts of the plant, not from palm to palm. 



All stages are found at all seasons of the year, the greater number 

 of active larvae occurring from March to December. In early spring, 

 during the migratory period, they mass together on the fronds and 

 fruit clusters, causing serious damage, which may result in the dropping 

 of the fruit and retarded development of the plant. The adult stage 

 is reached in about a month or less, according to the season. Field 

 observations indicate that the life of the scale lasts from six to nine 

 months. The proportion of adult males to adult females is exceedingly 

 small. 



The insects usually become buried to a depth of four or five inches 

 under the plant tissues, and are thus well protected from adverse 

 atmospheric conditions and remedial measures. The main infestation 

 on mature palms is in the wliite living tissues of the leaf bases and 

 fibre bands from H to 3 feet down from the crown or from the fifth 

 to tenth leaf whorl. During the migratory period in April, May and 

 part of June the exposed fruit stems may become infested. Of the 

 root system only the so-called superficial roots have been observed 



