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| Wednesday, January 03, 2007 |
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2007 Grasshopper Forecast for Saskatchewan
December 2006
The grasshopper forecast map indicates that the risk of economically significant grasshopper populations will be low for Saskatchewan in 2007. In the southern region, sampling at a number of sites showed light infestations. Areas in both the southeast and southwest were identified with a few light infestations that could represent economic risk to more sensitive crops such as lentils. An area of moderate risk is also indicated near Fox Valley in the southwest. The warm, dry conditions, particularly those experienced later in the 2006 growing season, were favourable for grasshopper development and reproduction. The forecast map is based on adult grasshopper populations observed during a 2006 fall survey by Saskatchewan Crop Insurance. The survey includes approximately 1,150 sites, and is intended to reflect the number of adult grasshoppers potentially capable of reproduction and egg-laying. This information provides an estimate of eggs that can survive over winter and hatch the following spring, presenting a potential risk to crops for the 2007 growing season. The survey is directed at the adult stage of the population, since pest grasshopper species have an annual life cycle. Grasshoppers require a warm, dry climate for successful growth and development. Warm, dry conditions in the spring and early summer increases the survival rate of the hatchlings, and the potential for subsequent damage to crops. Heat later in summer and fall, as in 2006, encourages mating and egg-laying. The actual severity of a grasshopper infestation will primarily depend on weather conditions in the spring, as well as the level of last summer's grasshopper infestation in a given area. The survey and risk map are intended to indicate the general risk in the province. Producers should therefore be aware that actual levels of infestation locally or in individual fields may differ from those predicted in the 2007 forecast map. Producers should monitor for economic populations once the spring hatch has begun and crops emerge from the ground. Certain areas are more prone to grasshopper egg-laying. Female grasshoppers tend to lay eggs in areas with green growth, which is a potential food source for the hatchlings that are less mobile and cannot move great distances. Efficient weed control is important, as weedy fields are attractive for egg-laying. Areas with early green plant growth, such as field margins, fence lines, roadsides, and crops grown on stubble, should be watched closely when hatching begins in the spring. The low level of grasshopper numbers for most areas may provide a more suitable situation for producers attempting to establish forage crops that were severely affected by grasshopper feeding during the past outbreak. Note the label precautions regarding user safety and correct use of insecticides. Be aware of neighbouring fields, and have an understanding of how these fields may be affected by the application of the chemical. Take special care when using insecticides to control grasshoppers in close proximity to wildlife, and near environmentally sensitive areas such as ponds, sloughs and shelterbelts. Most insecticides have broad spectrum activity and can be fatal to beneficial insects such as bees, in addition to pest species. Strategies to avoid a negative impact on bees include the following:
Keep in mind that the objective is to sensibly control grasshopper populations to protect the crop. One hundred per cent elimination is not a realistic goal. Updates on the status of grasshopper populations in Saskatchewan will be available during the production season through the Agriculture Knowledge Centre. For more information,
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