Well, the first challenge of the sugarbeet season has been met — the beets are up. But wait! There are gaps in the row! And this seedling is wilted! And something has been chewing on these seedlings! What's going on?

A number of pests, both diseases and insects, can attack sugarbeet seedlings.

Organisms causing sugarbeet seedling diseases include Pythium, Aphanomyces, and Rhizoctonia. They may cause pre-emergence or post-emergence damping off, while seedlings which survive the infection may be weakened and stunted, or more susceptible to disease later in the season.

Pythium can infect seedlings at a wide range of temperatures under moist conditions (it can grow once soil temperatures reach 5°C or 41°F), while Aphanomyces prefers saturated soils and temperatures above 15°C (59°F). Rhizoctonia prefers even warmer temperatures, typically infecting beets only when soil temperatures are above 20°C (68°F). Another race of Rhizoctonia can cause Rhizoctonia root and crown rot later in the season. Sugarbeet varieties approved by the processor have tolerance to seedling disease. Fungicide seed treatments are also effective in controlling some of these pathogens.

A number of soil insects can feed on young sugarbeets. Cutworms and white grubs can cut plants off at or just below the soil surface. Black cutworm moths have been flying in on weather fronts from the U.S. for over a month now. They are attracted to areas with heavy green residue such as weed patches, where they lay their eggs. The larvae then emerge and feed on the crop. Scout fields every few days to look for areas of poor stand or plants that are cut off. When plants are small, control may be warranted if more than 5% of the plants are damaged. Lorsban 4E is the only product registered on cutworm in sugarbeets. White grubs may cause similar damage to cutworm, so be sure to dig around damaged plants to find the culprit. There are no control measures available for white grub in sugarbeets. For more information on cutworms, see the OMAFRA fact sheet, Managing Cutworms in Vegetable Crops.

Wireworms can feed on both the seed and seedlings. They are more likely to be found in sandier soils, under reduced tillage, or in fields where small grains, forage crops, or large weedy patches have been plowed under. Wireworm take 2-5 years to mature, so if they were present in the previous crop, they can be expected to be present in the current crop. Since the only chemical control for wireworm is an in-furrow treatment of Counter at planting, fields at risk must be scouted pre-plant to determine if control is needed. Scout by establishing bait stations. Bury freshly cut potatoes in nylon mesh bags, 10" deep in the field, with soil mounded over them to prevent water from ponding. Check the bait stations for wireworm larvae a few days before planting to determine if control measures will be needed. See OMAFRA Factsheet Managing Wireworms in Vegetable Crops for more information.

Flea beetles overwinter under crop residue or in other protected areas. They emerge in early spring and can cause severe damage to germinating sugarbeet seeds and small seedlings. Typical damage is numerous small holes on the leaves and cotyledons. With the cool temperatures this spring, the sugarbeets are growing slowly and thus have remained in a small, susceptible stage for a prolonged period of time. Control may be warranted when more than 25% of seedling plants show damage. Malathion 500 is the only registered control in Ontario.

Spinach leafminers also overwinter in the soil, with the adults emerging in early spring to lay small, white eggs on the underside of beet leaves. You can look for these eggs while scouting your sugarbeet fields. The young emerge and feed inside the leaves, making narrow, winding tunnels. Control lambsquarters in and around sugarbeet fields, as they are an alternate host for the leafminer.

Remember to scout fields often to be aware of developing problems. See OMAFRA Publication 363, Vegetable Crop Recommendations, for pest management recommendations for sugarbeets. As the Ontario sugarbeet crop is processed entirely in the U.S., all pesticides applied to the crop must have both Canadian and U.S. registrations on sugarbeets. Your processor may have specific restrictions and recommendations. Check with your processing company representative. Always read and follow label directions.