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Interaction of biology and behaviour of storage insects with environmental conditions in bulk grain - AR0603

ObjectiveTo provide the necessary background knowledge on the biology, behaviour and population dynamics of insects in the stored grain ecosystem in order to devise new strategies for their control or management by physical and biological methods.Research aspects1. Pest Biology: activity levels: Temperature limits for locomotory activity, for feeding, and for flight. 2. Pest Behaviour – response to environmental gradients and activity rhythms: Orientation in low movement air streams with respect to moisture, temperature, reduced oxygen and increased carbon dioxide. Movement in grain in response to moisture, temperature, and carbon dioxide gradients, and to gravity and light. Life cycle responses to photoperiod. 3. Population dynamics: Responses to temperature gradients and controlled air flows in larger scale tests, Physical cues for aggregation, factors controlling hot-spot formation by insects, population growth in bulk grain ecosystems, trends and changes in populations in grain bulks. 4. Parasitoid biology: Thresholds for parasitoid development, cues for flight and host location, host/ parasitoid population relationships.Policy relevance Knowledge of insect biology, particularly near the edges of growth limits, and of insect behavioural responses to environmental cues in the grain storage environment is the basis required for the development of new strategies to enable the industry to move away from reliance on pesticide application of one kind or another. It is departmental policy to minimise pesticide use due to concerns about residues in food, pesticide use generally and pesticide resistance. Non-chemical control measures will be vital to the establishing of sustainable and continued competitiveness of UK cereals in world markets. They are a must for this purpose and also for the increasing organic production market which requires procedures for non-chemical storage. Intended use of results The biological data obtained will provide the basis for selecting appropriate store management conditions for operating physical and biological control strategies. Information on insect lower temperature limits for various activities will provide guidance on the target temperatures to prevent population increases, and knowledge of insect responses to environmental gradients will influence developments in pest monitoring and trapping and population management by physical or biological methods. The data gained from the project would improve expert systems predicting pest population trends and advising on pest management strategies. The study of the interaction of the biology and behaviour of insects with the environmental conditions in bulk grain would underpin future lines of work in partnership with industry to progress towards pesticide-free grain storage.
1. To establish the lower temperature limits for adult and larval crawling locomotion in at least 4 species of external grain feeding beetles, plus, for adults, three species of internal grain feeders, during year 1.
2. To examine in grain bulks which species are able to cause hot spots (years 1 to 2).
3. To establish the lowest temperature at which grain pests feed and hence the threshold temperature for damage (years 1 to 2).
4. To assess the response of several grain pests to choices in low airflow systems of (year 1) of moisture or temperature differences and in years 2 and 3 to low oxygen or raised CO2 air streams in ‘y’ olfactometer tubes.
5. To assess the movement of insects in grain set up with gradients of temperature or moisture content in vertical or horizontal planes and in the presence or absence of light, in order to assess factors enhancing aggregation. Years 1 to 2 laboratory scale tests, years 3 to 4 larger scale tests.
6. To determine flight thresholds for beetles, moths and parasitoid wasps in a flight chamber (year 2).
7. To investigate the role of diurnal light cycles in control of hatch, eclosion, population movement and initiation of diapause in stored product beetles in Years 2 to 3 with termination of diapause and larger scale population studies in year 4.
8. To establish the extent of changes in food preferences and temperature/moisture content choices in new and long term laboratory reared strains of two common grain pests (years 2 to 4).
9. To establish the threshold temperatures for development of grain weevil parasitoids on their host, and the effect of host diet (years 3 to 4).
10. To examine the influence of airflow- mediated factors as established from objectives 4 to 6 to the response of whole insect population in grain bulks (Years 3 to 4)
Project Documents
• Final Report : Interaction of biology and behaviour of storage insects with environmental condition in bulk grain   (1015k)
Time-Scale and Cost
From: 2002

To: 2006

Cost: £655,327
Contractor / Funded Organisations
Central Science Laboratory
Grain Pests              
Pest and Weed Control              
Pest Control              
Plants and Animals              
Sustainable Farming and Food              
Sustainable Production              
Fields of Study
Arable Crops