Biological control in the Maltese Islands - past initiatives and future programmes

Past records of introduced predators and parasites for biological control programmes in the Maltese Islands are reviewed. Literature on this subject is very limited, difficult to obtain and to confirm. During the last 10 years, several exotic pest species were accidentally introduced into the Maltese Islands, including Aleurothrixus floccosus, Bemisia tabaci, Liriomyza spp., Frankliniella occidentalis and Phyllocnistis citrella. Natural enemies have been imported to control these pests. These include Dacnusa sibirica and Diglyphus isaea for the control of leafminers; Encarsia formosa, Eretmocerus califomicus and Macrolophus caliginosus for regulation of Bemisia tabaci; Cales noacki against Aleurothrixus floccosus; Orius laevigatus, o. insidiosus and Neoseiulus cucumeris against thrips; Aphidius colemani and Aphidoletes aphidimyza for the control of glasshouse aphids and Phytoseiulus persimilis and Amblyseius califomicus for the control of the red spider mite. Encarsia lutea and Eretmocerus mundus have been recorded from Bemisia tabaci in Malta. Faunistic studies of parasitic Hymenoptera occurring in Malta are currently being carried out. The data is presented and the significance of utilizing local natural enemies is briefly discussed.peer-reviewe

Robot control with biological cells

At present there exists a large gap in size, performance, adaptability and robustness between natural and artificial information processors for performing coherent perception-action tasks under real-time constraints. Even the simplest organisms have an enviable capability of coping with an unknown dynamic environment. Robots, in contrast, are still clumsy if confronted with such complexity. This paper presents a bio-hybrid architecture developed for exploring an alternate approach to the control of autonomous robots. Circuits prepared from amoeboid plasmodia of the slime mold Physarum polycephalum are interfaced with an omnidirectional hexapod robot. Sensory signals from the macro-physical environment of the robot are transduced to cellular scale and processed using the unique micro-physical features of intracellular information processing. Conversely, the response form the cellular computation is amplified to yield a macroscopic output action in the environment mediated through the robot’s actuators

Biological Control of Banded Leaf and Sheath Blight Disease (Rhizoctonia Solani Kuhn) in Corn with Formulated Bacillus Subtilis Br23

Rhizoctonia solani Kuhn. causing banded leaf and sheath blight diseases is one of the important fungi of corn world wide. The fungus is commonly controlled by using fungicide because no resistant variety available. The objective of the study was to develop a seed treatment formulation of the selected Bacillus subtilis to control R. solani in corn. The study was conducted in the Department of Plant Pathology, College of Agriculture, University of the Philippines Los Bañòs, College, Laguna from May 2004 to August 2005, using sweet corn var. IPB Supersweet as test plant. Corn seeds were surface sterilized for 10 minutes in 1% sodium hypochlorite solution and 5% ethanol, washed thrice with sterile distilled water and air-dried. The seeds were coated with formulated B. subtilis BR23 and used for several experiments, such as evaluation for their germination and growth in the laboratory, effectively on R. solani in the baked and nonbaked field soil under greenhouse condition, and in the microplots artificially infested with R. solani. The treatment was compared with other standard seed treatment of synthetic fungicides such as captan (10 g per kg seeds) and metalaxyl (10 g per kg seeds). The experiments were designed in a completely random design with three replications. Parameters observed were seed germination, plant height, disease scores, and plant yield. Laboratory formulated B. subtilis BR23 used as seed treatment had no detrimental effects on seed germination and seedling vigor. In microplots artificially infested with a selected highly virulent R. solani, seed treatment with the same formulation increased grain yield by 27% compared to that of the control captan seed treatment with 14.4%. The studies showed the potential of B. subtilis BR23 for commercialization as a seed treatment for the control of banded leaf and sheath blight disease (R. solani) in corn

A comparative assessment of the methods of control of water hyacinth infestation with regards to fish production

Water hyacinth (Eichhornia crassipes) has been subject of three control methods since its arrival into the Nigerian freshwater lagoon system in 1984 - mechanical, chemical and biological. An assessment of these three methods seems to suggest that mechanical and chemical control methods, both of which being costly, must be applied either solely or integrated to combat the present level of considerable infestation in Nigeria. The biological control methods are advisable for slow, sustained control and can only cope with low levels of infestation. It is thus concluded that the preliminary control method should be mechanical or chemical to effectively abate the nuisance plant, followed by biological control once infestation levels have been sufficiently reduce

Biological control in French Guiana, Guadeloupe and Martinique

Several biological control agents have been introduced successfully in Guyana, and / or Guadeloupe and Martinique: three tachinid dipterans and one hymenopteran for control of sugarcane borers, a ladybird and a hymenopteran parasitoid against the pink hibiscus mealybug, a hymenopteran parasitoid to control Asian citrus psyllid, another hymenopteran parasitoid against citrus blackfly, and a hymenopteran parasitoid for control of fruit flies. Mass rearings of a lacewing and a Trichogramma egg parasitoid are being implemented in Martinique for augmentative biocontrol. Use of native natural enemies in conservation biocontrol projects is being initiated in several crops, after a period of intensive prospecting for natural enemies. A recently started project in French Guiana aims at control of the mango mealybug by introducing two exotic parasitoids

Opportunities for classical biological control of weeds in European overseas territories

European overseas territories are home to biodiversity and endemism of worldwide importance, vastly superior to that of continental Europe as a whole. They are, however, much more threatened by invasive species, including hundreds of alien invasive plant species having a huge impact on natural and agricultural habitats. As in continental Europe, invasive plants have only recently been recognized as a threat to the local environment and biodiversity. Mechanical and chemical control programmes - underway for several decades - have not been entirely successful for permanent, cost effective, environment-friendly management. Biological control of weeds has long been successfully used in other neighbouring countries with similar climates, environmental conditions and invasions, but has barely been implemented in European overseas territories. There have been very few attempts to set up cIassical biological control programmes in these regions - a few of the species that have been the focus of biological control are Lantana camara L.. Rubus alceifolius Poir., Opuntia stricta (Haw.) Haw., Acanthocereus tetragonus (L.) Britton & Rose, Ligustrum robustum (Roxb.) Blume, Miconia calvescens DC., Ulex europaeus L., Prosopis juliflora (SW.) DC., and Leucaena leucocephala (Lam.) de Wit. Many invasive plants occurring in European overseas territoties are also invasive elsewhere and already targets of biological control programmes. Biological control agent specificity requires particular attention due to the high level of endemism in such islands. This paper reviews some of the most threatening species for which classical biological control could be achieved through regional or international collaboration. (Résumé d'auteur

Improvement of biological control by volatile plant compounds

Compared to conventional farming the pest management strategies in organic farming is based on better plant resistance and sustainable cultivation technique that does not destroy the natural enemies of pest insects. Methods that reduce feeding efforts of pests and maintain strong population of predators and parasitoid on crop plant, are the way forward for sustainable plant protection strategies. Volatile compounds extracted from plants and sprayed on crop plants are one of the key factors for the development of these techniques

Entomopathogenic nematodes for biological control of codling moth

Entomopathogenic nematodes are often found naturally infecting codling moth larvae. The effect of an autumn treatment with S. feltiae on the fruit damage in the following summer was evaluated by treating 4 different apple orchards in October 2004 and 2005 at application rates of 3.75; 2 and 1.5 billion nematodes in 4000 l / ha. In three of the treated orchards, one treated with 3.75x109 nematodes/ha the other two treated with 2e9 nematode/ha, reduction in fruit damage was around 50%. In the most heavily infested orchard, which was treated with 1.5x109 nematode/ha only 33% reduction in fruit damage was achieved. Compared to previous studies, this was the first assessing the effect on the fruit damage in the summer following the treatment rather than assessing the mortality of sentinel larvae fixed to the treated tree trunks

Vector control for the chikungunya disease: chemical control versus biological control: a mathematical point of view.

The aim of this talk is to present recent investigations on the Chikungunya Disease that hitted Réunion Island, a French territory in Indian Ocean, in 2005 and 2006. Chikungunya is a vectorborne Disease, usually localized in Asia and East-Africa. In 2005, it was the first time that a developed country was affected by this virus. In July 2007, a small outbreak raised in Italy, indicating that the South of Europe is potentialy threatened. In recent works, we have proposed and studied a mathematical model to explain the outbreak of 2005 and possible links with the explosive epidemic of 2006. We also have focused our study in the comparison on different mosquito control tools (adulticide, larvicide, and mechanical control), in order to know if it would have been possible to contain or to stop the epidemic of 2006. Recently, a new project has began to check the feasability of the Sterile Insect Technique (SIT) as a tool for vector-control in Réunion Island. After a short review on the Chikungunya virus, its principal Vector, Aedes albopictus, and recent biological results, we will present the mathematical models developed to assess the efficacy of the vector-control tools used in Réunion Island. We will introduce the SIT project, provide some recent results, and compare them to the previous ones. Finally, we will end the presentation with some prospective works. (Texte intégral