104 



j\ro7XETTE (Cr. F.). U.S. Bur. Knt. The Dictyospermum Scale 



on the Avocado and how it may be controlled.— ^(^/^A'. Bull. 



State Plant Bd. Florida, (Hiiiicsvillc, v, no. 1, ()ctol:)cr 1920, 

 pp. 5-11, 1 plate. [Received 6th January 1921.] 



Chrysoniplialiis didyospermi, Morg., is a particularly destructive 

 scale on a\'(jcado in Florida, especially where the temperature is uniform 

 and in the more protected localities. Other fofxl-plants are Dictyo- 

 spci')iiitni album (the original host), Iirvthrina indica, sago and other 

 palms, tea, rubber [Ficus), Citrus, orchids, camphor, coconut, guava, 

 mango, pecan, rose, banana, and many others. The males have not 

 been observed in Southern Florida, and apparently the species is 

 parthenogenetic there. The young may be seen crawling about the 

 twigs and branches about 1st March. A generation at this time 

 requires about seven weeks to mature in the open ; during the warmer 

 months the life-cycle is shorter, and the generations overlap consider- 

 ably. In the cooler weather of December and January the life-c3'cle 

 occupies over 2i- months ; there are generally live or six generations 

 in a year. The insect is found only on the branches (the lower ones 

 for choice), twigs and leaves. It does not produce honey-dew, but 

 likes to shelter under the sooty mould produced by Trialeurodes 

 floridensis, Quaint, (avocado white-fly). A parasite of . considerable 

 economic importance is Aspidiotiphagus citrinus, Craw. 



Tests with various insecticides have shown that caustic potash 

 fish-oil soap, lime-sulphur solution and miscible oils are none of them 

 efficient, but one gallon of oil emulsion to 70 U.S. gals, water, used 

 twice during the dormant season, was found to clear the trees of 

 both C. dictyospermi and sooty mould, generally within about a week. 

 If separation of the oil occurs owing to the hardness of Florida water, 

 2 or 3 lb. of caustic potash fish-oil soap should be added to a 125 

 U.S. -gallon tank before the emulsion is put in. 



The Yam WeQVil—Qirly. Bull. State Plant Bd. Florida, Gainesville, 

 V, no. 1, October 1920. p. 27, 1 fig. [Received 6th January 

 1921.] 



The interception of Palaeopus costicollis, ]\lshl. (yam weevil) in 

 the luggage of a passenger from Jamaica to South Carolina is recorded. 

 The one yam contained 14 adults, 23 pupae and 12 larvae of this 

 insect, which is not yet known to occur in the United States. 



Sherman (F.). Report of the Division of Entomology.— ti^/^rf Ann. 

 Kept. North Carolina Agr'ic. Fxpt. Sta., lOlS-10, Raleigh, 1919, 

 pp. 54-58. [Received 6th January 1921.] 



Studies on the larger corn stalk borer [Diatraea saccharalis] have 

 extended over the last five years. It is found that numbers of the 

 over-wintering larvae are killed by ploughing the stubble in the autumn. 

 Injury is also reduced by planting after 25th May, as maize 

 planted after this date is attacked by only one generation of the 

 moth, while that planted earlier is subject to attack by two. Cabbage 

 worms [Pieris rapae] can be controlled by dusting the plants weekly 

 with one part lead arsenate to eight of air-slaked lime. 



A severe outbreak of the green clover worm [Plathypena seahra] 

 occurred among soy beans in July and August. Experiments showed 



