514 



Fungus diseases may kill from 16 to 35 per cent, of the larvae, 

 especially in wet weather, and a second generation, reduced by these 

 agencies, provides less breeding facilities for the parasites with the 

 result that in the following year their position becomes very 

 unfavourable, and a fresh outbreak of P. brassicae occurs later on. 



The best direct artificial measure against P. brassicae consists in 

 crushing the eggs and collecting the larvae. This may be supple- 

 mented by the capture of the butterflies, especially those of the first 

 generation. Preventive measures include the collection of non- 

 infested pupae, and the spraying of cabbage seedlings with a 2 per cent, 

 nicotine solution to repel the ovipositing butterflies. Spraying must 

 be repeated from time to time, as the repellent efiect has been found 

 to disappear in about 9 days. 



Smyth (E. G.). Report of the Division of Entomology. — Ann. Rept. 

 Porto Rico Insular Expt. Sta., Rio Piedras, 1st July 1917 to 

 30th June 1918, 1919, pp. 109-129. [Received 6th Oct. 1919.] 



Insect pests intercepted during 1917-1918 include: — Various Aphids 

 on flowering greenhouse plants from the United States, such as 

 Macrosipkum (SiphonopJiora) sp. on roses ; Pseudococcus spp. on 

 ornamental plants ; TetranycJms quadrimaculatus (red spider) ; the 

 leaf-tyers, Phlyctaenia fernigalis, Hb., and Tortrix {Archips) parallela, 

 Rob. ; Aleurodes vaporariorum, Westw. (greenhouse whitefly) ; fern 

 scales ; palm scales ; and mites. Thrips tabaci was intercepted on 

 onion seedhngs and a Psocid on pineapple seedlings from Hawaii. 

 Most of the species that are greenhouse pests in the United States are 

 capable of becoming very dangerous outdoor pests in Porto Rico ; 

 this has already happened in the case of the Nematode, Heterodera 

 radicicola. Interceptions from foreign ports included a Capsid, 

 probably Tenthecoris bicolor, on orchids from Venezuela ; a large 

 cockroach, perhaps Leucophaea sp., in the packing with orchids from 

 Santo Domingo ; the mite, Stigmaeus floridanus, Banks, in pineapples 

 from Cuba ; a new mealy bug, Pseudococcus sp., on carnations and 

 sunflowers from Santo Domingo ; a Ptinid beetle in cacao beans and 

 a Bruchid in Cassia beans from Santo Domingo ; many grain weevils, 

 Calandra oryzae and Spermophagus pectoralis, in maize and beans from 

 Venezuela and Santo Domingo. It is suggested that a regulation 

 should be promulgated requiring the fumigation of every load or 

 shipment of grain entering the Island from a foreign port. Rigid 

 quarantine measures have been maintained against importations of 

 Citrus, and were extended in February 1918 to pineapple fruits or 

 plants. 



A series of experiments is to be undertaken to determine the 

 possibility of dissemination by insects of the motthng disease of sugar- 

 cane. Possible factors in this respect are Tettigonia similis, Wlk., 

 a green leaf- hopper found on Para grass in the vicinity of canefields, 

 or Xyleborus sp. (cane shot-hole borer), which was abundant in 

 decaying cane seed stalks in a field that was badly infested and where 

 the disease was spreading rapidly. 



The damage by white-grubs [Lachnosterna] to sugar-cane is increasing. 

 In some localities where they have not been very abundant in previous 

 years it is now necessary to resort to hand-picking. There is great 

 need of some cheaper and more efficient remedy for white-grubs in 



