2019 Saskatchewan Grasshopper Forecast
Although conditions were dry in much of the province in 2018 and favoured grasshopper population growth, low population levels in 2017 likely contributed little to 2018 populations. As a result, the 2019 Grasshopper Forecast indicates low risk for most of Saskatchewan for grasshoppers. However, some locally-large numbers were reported in 2018, and some crops such as lentil can have economic damage with lower densities of grasshoppers. Monitoring your fields is still essential.
The grasshopper surveys are based on observations of adult grasshopper numbers in the late summer that are capable of reproduction and represent a risk to crops the following year. Grasshopper populations have more successful development in dry years and increase more dramatically over a series of dry years. Population growth was seen in Alberta and Manitoba in 2018.
The 2019 forecast map is based on observations by Saskatchewan Crop Insurance field personnel in August and September of 2018 at about 1200 sites in the Province. The survey estimates the number of mature grasshoppers capable of reproduction and egg-laying prior to winter.
The survey and Forecast Map are intended to provide general information on risk levels. The actual severity of grasshopper infestations may differ from the 2019 Forecast Map depending on weather conditions in the spring. Hot and dry conditions favour growth and development of grasshoppers.
Not all grasshoppers are crop pests. The grasshopper survey is intended to consider annual species because they have a greater potential for rapid increase in populations. Grasshoppers that are already winged adults before June, have coloured wings or make audible sounds are considered non-pest species and rarely cause economic damage. Many of these are rangeland species and require two-years to complete their life-cycle and do not tend to increase to economically damaging numbers.
Growers should monitor for young grasshoppers in susceptible crops in the spring and early summer. Lentil flowers and pods and developing green bolls in flax are especially vulnerable to grasshopper feeding. In both of these crops, grasshopper feed on reproductive parts of the plant rather than foliage and therefore have a more direct effect on yield with a lower economic threshold of two grasshoppers per square metre.
Contact the Agriculture Knowledge Centre (1-866-457-2377) for further information on grasshoppers and updates during the 2019 growing season.
Download the 2019 Grasshopper Forecast Map