8 



40 gals, water should not be used, especially in the first two appli- 

 cations. The time of application of the sprays is most important and 

 differs according to the varieties of tree to be treated. The best time 

 for treating some of the commoner varieties of apple is discussed. 



Ballou (H. a.). The Brown Hard-back Grub in Antigua {Lach- 



nosterna antiguae. Arrow). — West Indian Bull., Barbados, xix, 

 no. 1, 1921, pp. 1-17. [Received 2nd November 1921.] 



The early records of occurrence of the brown hard-back grub of 

 Antigua (Lachnosterna antiguae, Arr.) since about 1911, when attention 

 began to be drawn to it, are briefly reviewed. Within the last few 

 years there seems to have been a general development of soil grubs 

 as pests of sugar-cane in different parts of the world. In Barbados, 

 the attacks of the root-borer, Diaprepes ahhreviatus, and of the brown 

 hard-back, Lachnosterna {Phytalus) smithi, have attained considerable 

 importance, but planters do not seem to have formed any precise 

 opinion as to the damage done to sugar-cane by the latter. Knowledge 

 concerning L. antiguae has been obtained from observations extending 

 over a number of years, largely during brief visits to Antigua. Details 

 are given of extensive examinations of the soil, healthy and unhealthy 

 cane plants and number of grubs present. These show that there is 

 no characteristic appearance of the canes to indicate attacks bj^ soil 

 grubs. Perfectly healthy canes have been found in some very heavily 

 infested spots, while badly diseased canes have been found where 

 very few grubs were present. Neither is there any constancy in 

 the numbers of grubs in the soil at the root of badly diseased canes. 

 Generally speaking, it seems as though heavy soils, with insufficient 

 drainage, contain more grubs than lighter soils, but heavy infestations 

 were also occasionally found in healthy stools grown in light soils 

 under good conditions. 



The system under which sugar-cane is grown in Antigua is discussed. 

 It is considered that the practice of forcing the land, especially that 

 under contract to grow crops for the factory, is responsible for much 

 of the so-called root disease, which is frequently attributed to cane 

 grubs. The importance of proper agricultural practice, such as 

 manuring, frequent tillage, the use of green dressing and drainage, 

 and the introduction of a proper rotation crop at frequent intervals, 

 is emphasised, root disease conditions having been eliminated by these 

 methods. 



A translation of Arrow's description of L. antiguae [R.A.E., A, 

 ix, 90] is given. The life-history has not been fully worked out. 

 The first beetles issuing from the soil were collected on 8th March ; 

 those collected previously, from 29th January onwards, were either 

 in pupal cells or at such a depth in the soil as to indicate that they were 

 not ascending, although out of the pupal cell. Eggs were found in 

 the soil in May and July in 1919. Grubs were found in the soil at 

 all times from May 1919 to May 1920, and at all seasons there were 

 full-grown larvae. Small and half-grown larvae are recorded from 

 May to September 1919 and again in May 1920. Pupae were found 

 in March 1919. The season for pupation and transformation to the 

 adult seems to be a very definite one, the emergence of the adults 

 from the soil seeming to depend upon sufficient rain to soften the 

 surface of the soil. Attempts to rear the insect from egg to adult 

 in confinement have been unsuccessful. The indications are that from 

 3 to 5 days are passed in the pre-pupal stage and from 17 to 25 as a 



