REPORT ON A TRIP TO DEMERARA, TRINIDAD AND
BARBADOS DURING THE WINTER OF 1913

By GEORGE N. WOLCOTT.1

Late in the autumn of 1912, I made a trip to Demerara, Trinidad, and Barbados to investigate certain aspects of the cane insect problems in those countries for the Porto Rican Board of Agriculture, and in the interest of the sugar planters of Porto Rico.

It would not have been possible for me unaided to have made observations of much value, had I not received the heartiest coöperation from various persons, particularly the Entomologists of the countries visited. Especial mention should be made of the assistance rendered by Mr. J. B. Harrison, Director of the Botanical Gardens, Mr. G. E. Bodkin, Government Economic Biologist and Mr. J. J. Quelch, Entomologist for the cane growers, of Demerara; Mr. F. W. Urich, Entomologist of the Board of Agriculture at Trinidad; Mr. J. R. Bovell, Director of the Local Department of Agriculture; Mr. Wm. Nowell, the Assistant Director, Entomologist and Mycologist, and Mr. H. A. Ballou, Entomologist of the Imperial Department of Agriculture for the Lesser Antilles, at Barbados.

The methods of growing cane, and the conditions of labor, soil and climate are different from those common in the southern United States. It will be necessary, therefore, to tell something of them before one can obtain an appreciation of the injury caused by the pests of cane and the effectiveness of the control measures adopted.

In Demerara, all the cultivated area in cane consists of a strip of land, varying in width from one to three or four miles, running along the coast-sometimes close to the ocean and only protected from it by the barriers, similar to the levees in Louisiana, which protect the fields from the overflow of the rivers, in other cases separated by miles of low marsh land from the sea. Although in recent years. there has been a considerable consolidation of the estates, the typical cane estate consists of a narrow strip of land, sometimes only a quarter of a mile wide, which runs back from the ocean into the wild, uncultivated and often unexplored interior. The typical arrangement is a road extending from the mill back through the cultivated area, on one or both sides of which is the main canal or ditch--fifteen or twenty feet wide. Each ditch has numerous side branches at regular intervals, leading back between the fields. The estate is entirely dependent upon these ditches for the transportation of the cane from

1 Published by permission of J. T. Crawley, Chairman of the Science Committee of the Board of Commissioners of Agriculture of Porto Rico.

the fields to the mill. After the cane is cut, it is placed in steel barges, which are towed along the canal and finally pass into the mill, where the cane is lifted by slings on to the carrier.

These beds are

The cane is grown in beds about thirty feet wide. separated by small ditches one to two feet wide. The ditching is necessary as the soil is heavy and the drainage poor. The rows of cane usually run crosswise of the bed, but in some fields where the land is not quite so heavy and the drainage is consequently better, the rows of cane are lengthwise of the bed. This arrangement might permit of mechanical cultivation which is not possible where the cane is grown in short rows.

Labor is one of the most serious problems on the plantations as the native Indians will not work, the negroes are unreliable and it is only the indentured coolie labor from India that can be relied upon. These men must work for five years without remuneration, the only expense to the employer being the cost of the laborer's passage from India and his subsistence. During the next five years, the coolie receives the average market wage per day, minus one shilling (24c.) but must pay this shilling even on days that he does not work. At the end of ten years he is free to return to India, or move to town, or to any other estate. Coolies newly arrived from India can not be used for the hand control of insect pests because of their religious scruples, but boys of the second generation, born in the colony, prefer this work to any other.

In Trinidad the labor supply is much as in Demerara, as the coolies do most of the work, although sometimes natives and negroes are seen at work in the fields.

The cane in Trinidad is grown in a comparatively restricted area. along the west coast between Port-of-Spain and San Fernando. The land is better drained, higher and of better texture than in Demerara. The cane is grown in level beds with the rows lengthwise of the bed, but despite the fact that the drainage ditches do not cut up the fields any more than in Louisiana, mechanical cultivation is seldom attempted.

The agricultural practice most noticeable is that of abandoning cane fields that are not producing a profitable tonnage. Even on the best managed and more profitable estates, one sees fields abandoned, growing up to weeds and grass, and pastured to oxen, with a few stalks of cane remaining to show what was the former crop. Upon the froghopper, Tomaspis varia Fabr., the most serious insect pest of cane in Trinidad, a bug that stunts or kills the cane by sucking the juice from the roots, is placed the blame for the abandonment of these fields. It is easy to see, however, that in an industry as un

profitable as is sugar production at present in Trinidad, the tendency would be to cultivate only the more productive fields. How unfortunate and undesirable this practice is in connection with attempting to control the insect and fungus pests of cane will be discussed later. In Barbados, the methods in vogue are the result of very cheap and abundant labor, the high price of land and the nature of the water supply. Everything is done on the most minute scale and by most antiquated and laborious methods. The island itself is small, and two thirds of the entire area is devoted to the cultivation of sugar cane. Modern factories are unknown and the cane is ground by small mills, which, in the majority of cases are driven by windmills. Most of the windmills are of the picturesque four-armed Dutch type. In some cases the rollers are vertical, although most of them are horizontal, and the cane is fed to the crushers by hand. The interior of the factory is very clean and sanitary, but everywhere manual labor is used instead of machines. Two men work the big ladle which transfers the juice from one evaporating pan to another and the concentrated juice is carried to the centrifugals in pails on the heads of negro women.

Another result of the cheap labor is that it is possible to cultivate the cane much better and cleaner than is done anywhere else. The entire absence of weeds is indeed remarkable and the more so when one considers that although the straight rows seem to invite mechanical cultivation, it is never attempted. The soil is black and of very good texture, but thin in most places. The coraline rock outcrops in many places and is never far beneath the soil. Rainfall in Barbados is comparatively slight and were it not for the coral rock, which acts as a sponge, conserving the rainfall and soaking up water from the sea, agriculture would be impossible. Capillarity brings the water up in to the soil from the surface of the rock and even in the dryest seasons the soil is moist at the depth of a foot. Soil moisture is further conserved by a thick mulch of cane trash, which is placed about all young plant cane. The wind often blows it away and it is carefully put back in place by the laborers.

From this short outline of the varying conditions under which cane. is grown in Demerara, Trinidad and Barbados, it might well be expected to find a similar diversity in the insect pests affecting the cane. Such, in general, is the case. The cosmopolitan Diatræa saccharalis Fabr., however, occurs in all the countries and does more injury to the stalk than any other insect. Pseudococcus calceolaria Mask., is also a common pest on cane, but its injury is not so generally considered serious. In Demerara, the smaller moth borer, Diatræa saccharalis Fabr., and the closely allied species, D. lineolata Walker and D. canella

Hampson, are undoubtedly the most serious pests of cane. The importance of the smaller moth borer is recognized by the planters and managers, and most strenuous measures have been adopted for its control. On practically every estate there are gangs of boys, sometimes as many as fifty in a gang, who do nothing else the year round but cut out the dead hearts which have been caused in the

young cane shoots by the Diatræa larvæ. The boys receive 6 cents per 100 for the larvæ and every effort is made to make the work thorough and systematic. There is a tacit understanding between the boys, however, that the collection of 700 is a fair day's work (and this represents more than a fair day's wage for a man) and they make no particular effort to collect more than about that number. It shows how serious the pest is, that the boys have no difficulty in collecting this number of larvæ day after day. The first impression one receives on going into a field of cane ready to be cut, is what an enormous amount of damaged cane is present. It is not at all difficult to find stalks with Diatraa holes and burrows in every internode, and it is practically impossible to find a single stalk of uninjured cane. For the ordinary varieties of cane this would mean that there would be practically nothing left worth grinding, but in Demerara, this problem has been met, though not solved, by the almost universal use of a local seedling cane, Demerara, 625. Although not highly resistant to Diatræa, it is more so than the older varieties and it is a valuable cane to plant for that reason, despite its low sucrose content.

The problem of controlling Diatraa is most seriously complicated in Demerara by the wet and dry seasons. There are always two and sometimes four wet seasons, and of course as many dry. Cane is cut towards the end of each dry season and seed cane will be planted at each wet season. As it takes from a year to eighteen months for the maturing of a crop, it can readily be seen that cane in all stages of growth is present on a single estate at all times. This means that there is always present, as partly or fully grown cane, a continuous and abundant source of re-infestation of the fields of young cane from which all the dead hearts have been cut out. Moths will fly out a hundred yards or more from the older cane, and more especially from cane that has been cut, depositing eggs on the young cane from which all the dead hearts have just been cut out, and in two or three weeks, the infestation will be as heavy as though no control had been attempted.

In addition to the attempted control of Diatraa by artificial means, the numbers of the pest are still further greatly reduced by parasites, four of which are present in Demerara. Two are parasites of the egg

and two of the larva. The cosmopolitan and ubiquitous Trichogramma minutum (pretiosa) Riley is everywhere abundant, and it is always easy to find egg clusters parasitized-indeed it is sometimes difficult to find clusters not parasitized. This high ratio of parasitism may be more apparent than real, as the black parasitized egg masses are very easily detected, but those not parasitized, being semi-transparent and light yellow in color, are much more difficult to see and not so many are collected. Another egg parasite, probably Telenomus sp., is also present in considerable numbers. A characteristic habit of Telenomus which makes it of much less value as a parasite, is that of neglecting to infest all the eggs in a cluster. Often as many as four or five eggs are thus allowed to hatch.

The adults of Iphiaulax sp., the braconid larval parasite, are quite noticeable in the field, as the red thorax and abdomen, very long black ovipositor and black and yellow wings make them conspicuous. The boys cutting out dead hearts often find six or seven larvæ or cocoons of this parasite in a day. This means almost exactly 1 per cent. of parasitism. Mr. Bodkin has also bred Tachinid. flies from puparia which the boys had collected in dead hearts, but these are much less common than the Iphiaulax.

In addition to having the boys cut out dead hearts, they are also paid one half cent each for Diatræa egg mass that has not turned black or red, which are considered to be nonparasitized, but this practice is by no means general. Most managers are theoretically in favor of it, because it removes the insect before it has done any injury, but the practical impossibility of getting all, or even a large part of the clusters, makes it impractical except in connection with the cutting out of dead hearts. The cost of keeping large gangs in the field the year round is very considerable, for the boys who cut out the dead hearts have work throughout the year as it takes three or four weeks to go over an estate thoroughly and they immediately recommence. It is difficult to say whether the cutting out of dead hearts does control Diatræa in a measure or not, but one is safe in saying that Diatræa injury would be much more severe, were it not done. It certainly is true that to be effective, it must be well done, and when negro women and girls are used instead of the coolie boys, the value of their work is problematical, for in addition to failing to cut out all the dead hearts, the women also cut perfectly healthy shoots.1

The coolie boys, far from being so stupid as to cut healthy shoots, are so bright that they have been known to substitute the larvæ of wasps for the Diatrœa larvæ, which they somewhat resemble in general appearance and are, of course, much more easy to obtain in large numbers. The unsuspecting overseers, who look over what the boys have collected, are none too observant, and often the deception passes.