Human health issues arising from the use of synthetic pesticides and concerns about their environmental toxicity are making lower-risk alternatives increasingly attractive. Biological control agents are living organisms which reduce harmful pest populations. Many people know of the common ladybird, whose larvae feed on aphids, but a wide range or biological control agents – e.g. predatory and parasitic insects, diseases of plant pests – are available. However, their use is still limited, in particular in low- and lower-middle-income countries.
Example of Ecological engineering in Vietnam (Photo credit: Dr HV Chien)
The rice ecosystems are inhabited by more than 100 species of insects. Twenty of them can cause potential economic losses. With the change in the climatic factors and modern cultural practices adopted for production a drastic change has been caused in the pest scenario in the recent past. Besides stem borer, gall midge, brown plant hopper and green leafhopper which were the major problems in past, several other relatively minor pests such as leaf folder, armyworms, cut worms etc. have gained importance. In a study conducted by the International Rice Research Institute (IRRI), it was found that, on average, farmers lose 37% of their rice yield to pests and diseases, and that these losses can range between 24% and 41% depending on the production situation (http://irri.org). All the pests are generally kept under check by their natural enemies (parasitoids and predators) by feeding on them. The food web of their relationships prevents the explosion of their populations and keeps them under economic thresholds mimimising the pesticide use.
The fifth edition of Biological Control of Weeds: A World Catalogue of Agents and Their Target Weeds has been released after years of literature searches and the involvement of 125 weed biocontrol specialists.
The publication of this catalogue, available as a searchable online database and as a PDF book, was led by Mark Schwarzländer, University of Idaho CALS professor of entomology and biological control of weeds (and a former CABI researcher), and current CABI biological weed researcher, Hariet Hinz. Several prominent invasive species researchers co-edited the catalogue, including CABI’s Chief Scientist, Matthew Cock. Continue reading
The Coffee Berry Borer, Hypothenemus hampei, is a tiny beetle which is widely considered to be the most damaging pest of coffee plantations in the world. Originating in Africa, it is now found in almost all coffee growing areas in the world as an invasive species, with nearly 160 records from different areas worldwide on the Plantwise Distribution Map. Coffee is an extremely important commodity in many countries, including Brazil, Peru, Columbia, Vietnam, India and Indonesia. CABI is currently running a project led by Soetikno S. Sastroutomo in partnership with the Indonesian Coffee and Cacao Research Institute (ICCRI) and Papua New Guinea Coffee Industry Corporation Ltd (CIC) to address problems with the Coffee Berry Borer in Indonesia, where over 920,000 ha of coffee are infested, 95% of which are farmed by small holder farmers. Papua New Guinea is one of the last two remaining coffee nations without the pest, so the project also aims to prevent the establishment of the pest in Papua New Guinea and save the country’s extensive coffee growing areas. The CABI project is applying knowledge from Coffee Berry Borer management in African and Latin American countries to create a country-specific management program with an emphasis on Integrated Pest Management techniques and training for farmers in order to combat the Coffee Berry Borer. A recent paper published this year highlights the potential for Integrated Pest Management (IPM) programs in the management of Coffee Berry Borer, using a case study from a large coffee plantation in Colombia. Farm managers and harvest workers received training workshops on pest management strategies based on prior research and the recommendations of the National Coffee Research Center in Columbia in order to implement effective IPM strategies. Continue reading
Native to Mexico, the papaya mealybug (Paracoccus marginatus) is controlled in its home range by endemic natural enemies, like the parasitoid Acerophagus papayae. When the papaya mealybug invaded a number of countries in the neotropical region, including the Caribbean, US and parts of South America, encyrtid parasitoids (in particular A. papayae) were introduced to control these pest outbreaks. While these earlier invasions have been managed using biological control methods, the papaya mealybug has still spread to the oriental region, critically damaging papaya crops. In an attempt to restrain the effects of the papaya mealybug studies have been conducted across the region, leading to a recent report that the pest has now spread to Malaysia.
Aspergillus flavus and A. parasiticus are important fungal pathogens that infect a wide range of cereals, oil seeds and nuts. They produce toxic metabolites called aflatoxins (mycotoxins with carcinogenic and teratogenic properties) that can contaminate food products. Although strictly regulated around the world, aflatoxin contamination in developing countries is poorly regulated. In addition, limited management options and lack of agricultural resources have led to repeated outbreaks of acute aflatoxicosis, fatal to many. Two recent studies on strains of A. flavus may provide a new route for aflatoxin management.
Mexico is the latest to succumb to the inevitable spread and establishment of huanglongbing (HLB) – the devastating disease of citrus crops. Mexican authorities in the states of Jalisco, Michoacán and Colima have warned growers that HLB – otherwise known as citrus greening – is here to stay.
HLB was first detected in Mexico in July 2009 and it’s clear now that it won’t be going away. Some estimates suggest HLB could affect 60% of Mexico’s citrus industry, an industry which provides employment for 70,000 farmers. SENASICA, the National Service for Animal and Plant Health, Food Safety and Quality, has invested over US$20 million to control the disease. An economic impact assessment report prepared this year by consultants specializing in the economics and finance of plant health programmes indicated total losses to the Mexican economy could amount to almost $7000 million.
Mexico’s not the first to report the alarming consequences of HLB infection. The disease has been known in Brazil for some years and is spreading throughout the region. Florida first reported the disease over 5 years ago and data from 2010 showed 18% of trees in Florida are infected – for more information on the disease in Florida click here. HLB was first reported in Nicaragua and Honduras in 2010 and in Costa Rica in February this year. A recent outbreak in the Dominican Republic is said to have destroyed 34,000 trees and left 5000 unemployed.