SWEET CORN POTENTIAL FOR CULTIVATION IN TRINIDAD AND TOBAGO

Results of research work conducted in the Faculty of Agriculture on sweet corn (Zes mays L. var. saccharata Sturt) are discussed and the potential for the cultivation of the crop indicated. A new high yielding (over 35,000 marketable cobs per ha) synthetic cultivar, Local F7, developed at the University is identified. ----- Los resultados del trabaj 0 de investigacidn del choclo (Zea mays L. var, saccharata Sturt) llevados a cabo en la Facultad de Agricultura son discutidos y la posibilidad para su cultivo es indicada, Se identifica una variedad, sintltica-criolla F7 de gran rendimiento (mls de 35,000 mazorcas para rnercadeo/ha), desarrollada en la Universidad de West Indies

ASSURE - A NEW SELECTIVE HERBICIDE FOR THE CONTROL OF ANNUAL AND PERENNIAL GRASS WEEDS IN BROADLEAVED CROPS

Assure [2-[4-[(6-chloro-2-quinoxalinyl)oxy]-phenoxy] propionic acid, ethyl ester], (formerly DPX-Y6202) is a new post-emergence herbicide for the selective control of annual and perennial grasses in broadleaved crops. It was evaluated in a wide range of broadleaved field crops, including vegetables, on different soil types and seasons in Trinidad and showed excellent activity against grass weeds including Brachiaria spp., Cvnodon dectylon, Digitaria spp., Eleusine indica, and Paspalum spp, None of the herbicide treatments caused any apparent damage to crops or significant taints in crop products. Annual and perennial grasses were controlled by rates between 0.05 to 0.1 kg a.i ha-1. ----- Un nuevo herbidda de post-brote-Assure- [2-(4-( (6·cloro-2-quinoxalinyl) oxyj-phenoxyj-acido propionlco, ester etilfcoJ, (anteriorrnente, DPX-Y6202), sirve para el control selectivo de hierbas anuales y perennes, en cultivos de hojas anchas incluyendo, verduras y en una variedad de suelos y estaciones, a la vez mostrando tener una potencia excelente contra las hierbas de pas to, incluyendo entre elias la Brachia ria spp., Cynodon dectylon, Digitaria spp., Eleusine indica y Paspalum spp. Ninguno de los tratamientos con herbicidas, causa daftos apparentes a los cultivos o descoloraciones en los productos de cultivo. Los pastes anuales y perennes fueron controlados por tazas entre los 0.05 a O.lkg a.i. ha-l

THE PERFORMANCE OF TROPICAL SOYABEAN CULTIVARS IN TRINIDAD

Four tropical soyabean cultivars (TGX 849-294, TGX 536-02, TGX 539-5E and TGX 306-036) from the International Institute of Tropical Agriculture were evaluated in a series of field trials on the University Field Station and cooperative farmer plots. In the planting date study the cultivars gave seed yields ranging from 1,800 to 3,800 kg/ha but exhibited slight response to photoperiod. They flowered in 40 to 70 days and matured in 97 to 138 days after planting with plant heights at harvest ranging from 50 to 90 cm. In the soyabeari/cassava intercrop study, sole crop yield of TGX 849-294 averaged 2,878 kg/ha as against 1,170 kg/ha in the intercrop. The cassava yield of 23,000 kg/ha compensated for the lower soyabean yield in the intercrop. In all trials the four cultivars were confirmed as promiscuous nodulators and generally performed better than the American cultivar, Jupiter. The tropical cultivars did not succumb to any serious pest or disease problem, showed excellent shatter resistance, rapid leaf senescence at maturity and improved seed viability. Cultivar TGX849-294 which matured theearliest and produced the best yields of excellent quality yellow seeds with protein contents of 40 % and oil content of 20 % was identified as the cultivar best suited for cultivation under local conditions. ----- Des cultivars de Soja (TGX 849-249 ; TGX 536-02 ; TGX 539-5E et TGX 306-036) en provenance de l'Institut International d'Agriculture Tropicale sont évalués dans une série d'essais à la station expérimentale de l'Université et chez l'agriculteur. L'étude dates de plantation montre que les cultivars ont donné des rendements allant de 1 800 à 3 800 kg/ha mais présentent une certaine sensibilité à la photopériode. Ils fleurissent après 40-70 jours et mûrissent après 97-138 jours avec des tailles de 50 à 90 cm. Dans l'association soja/manioc, le cultivar TGX 849-294 donne 1 170 Kg/ha contre 2 878 Kg/ha en monoculture. Le rendement en manioc de 23 000 Kg/ha compense le faible rendement en soja. Dans tous les essais les quatres cultivars présentent une nodulation hétérogène mais se révèlent être plus performants que le cultivar américain, Jupiter. Ils n'ont succombé à aucun ravageur revieux ni à aucun problème de maladieet présentent une rapide sénescence foliaire à la maturité et une viabilité accrue des graines.Le cultivar TGX 849-294 qui est le plus précoce et le plus productif en graines jaunes d'excellente qualité, avec des teneurs en protéines de 40 % et en huile de 20 % a été identifié comme le cultivar le mieux adapté aux conditions locales

Economic importance of White Top (Parthenium hysterophorous L. [f]) under intense vegetable production in Trinidad

A weed survey conducted to determine the incidence of Parthenium hysterophorous l. (f) in vegetable crops during the wet and dry seasons in Trinidad indicated that the plant is a predominant noxious weed. It has shown the ability to survive bipyridylium herbicide treatments, and biological and cultural control was insignificant in reducing the population of the weed. The weed reduced crop yield in tomato (lycopersicon esculentum Mill.) cv, Calypso by 10~ and crop quality in Cauliflower (Brassica aleracea var. botrytis l.j by 75-100% due to its competitive ability and allelopathic potential. The plant served as a suitable 'resting site' for the adult insect pest Plutella xylostella (l.) (Lepidoptera: Yponomenitidae) which attacks cruciferous crops

Guidelines for the identification and diagnosis of damage in crop plants caused by insects, diseases, weeds and nutrient disorders

The diagnosis implies an investigative approach to the problem. In any diagnostic consideration, you are first concerned with the nature of the effect. Is it biological? Causes by any physical agent? or it is due to the lack of some element or principle that is required by the plant for healthy growth and normal development. A conscious plan is developed for the ecological, biological and physical requirements of the plant