IN this week’s NAREI In Focus, we seek to highlight some of the challenges which may arise from time to time when cultivating exotic vegetables and recommend mitigation efforts which can be used to reduce instances of crop loss. One of the most significant problems with growing high-value crops in Guyana is that most farmers tend to grow multiple exotic crops that belong to the same family like that of Brassicaceae (Cruciferae) of which cruciferous vegetables like broccoli, cauliflower and kale belong. Consequently, growing a variety of these exotic crops make them susceptible to attacks from the same kind of pests and diseases.
Over 88 percent of farmers experienced such pest attack as a result of planting vegetables of the same family together. Based on this trend, the extension arm of the National Agricultural Research and Extension Institute (NAREI) has been encouraging farmers to adopt crop rotation as a medium of ensuring fewer losses with regard to pest and disease attack.
Chief Executive Officer of the National Agricultural Research and Extension Institute (NAREI) Dr. Oudho Homenauth has stated that while such instances have been evident, there has been a reduction in cases of pest and disease attack due to farmers being more educated on the importance of crop rotation to manage and mitigate pest and disease attacks.
The most common pests identified are White Flies, Leaf Miners, Aphids, Thrips, Worms, Nematodes and Diamond Back.
“In instances of pest and disease attacks, farmers can utilise both chemical and biological method of control. Interestingly, approximately 31 percent of farmers rely on both methods of pest control. The most commonly used are CAPRID (a systematic insecticide suitable for whiteflies and thrips among others; ABAMECTIN (targets caterpillars, leaf-miners, mites and diamondback); TRIAZOPHOS (a trans lamina, broad-spectrum insecticide); CHLOROPYRIFOS (contacts, persistent, termites and many other insects); FASTAC 5 EC and KARATAX both of which are contact and effective on many insects “ he said.
Additionally, a neem-based concoction and Jeye’s fluid solution are also alternative pest control for insects such as ants and whiteflies. With regard to biological control neem is seen as an effective measure used to deter the identified pest attacks. This can be used in the form of teas, concentrate or oil.
“In addition to these, farmers can also utilise other natural remedies using a solution containing soap, hydrogen peroxide or pepper such as cayenne; herbs such as holy basil and roots such as ginger and turmeric” he added.
Pest Control Application:
Concerning pest-control application, this can be applied either to beds before or after transplanting. However, the vegetable would need to be closely monitored and a follow-up application along with preventative measures during crop growth. It is advised that farmers monitor crops more during the wet season as diseases and root rot are often more prevalent during the wet season. The most common diseases and disorders identified among exotic farmers are various fungi, most notably anthracnose, powdery mildew, club rot, blossom end rot and root rot.
Bacterial diseases such as bacterial soft rot are also common during this period as these are brought on by pest attacks such as leaf curl and root rot due to nematodes. Additionally, wilting and spotting on leaves are also commonly observed during the wet season.
Methods for disease control among exotic farmers can be grouped into two categories namely through the use of natural remedies and best practices or via fungicide application. The most popular antifungal and antibacterial sprays used among farmers are CARBENSIZIM (systematic, broad-spectrum suitable for root disease); ACROBAT (broad-spectrum, contact and systematic); RIDOMIL (systematic, controls soil and leaf diseases); BELLIS (systematic, effective vs. many fungi) and COPAC which is a bactericide).
While the use of chemical control is effective, farmers can also effectively utilise natural remedies (identified prior) and best practices which include uprooting affected crops to prevent the spread of the fungus, scattering leaves or branches underproduce to prevent rotting and soil solarising using ultra-violent plastic to control soil-borne plant pathogens. Continually planning rows of one exotic crop on the same plot is known to build up the population levels of pathogens in the soils. As such, NAREI recommends crop rotation to reduce pathogens in the soil that cause diseases.