Strictly speaking, sugar beets are not a specialty crop, but seeing as they are only high produced in a dedicated region of the U.S., they are special. That’s why making sure hearty crops are available for harvest is so important.

Sugar beets generally account for about 55% of domestically produced sugar, with sugarcane accounting for the remaining 45%. The top sugar beet producing states are Minnesota, North Dakota and Idaho.

Like any other crop, sugar beets have to contend with disease and pest pressure. The sugar beet cyst nematode (SBCN) is one of the most economically devastating soilborne pathogens affecting sugar beet production not just in America but worldwide. SBCN can cause significant damage, resulting in stunted growth, leaf yellowing and substantial reductions in both yield and sugar content.

Evaluating composts and manures for managing SBCN is a team from the Department of Entomology at Michigan State University consisting of Ali Yaghoubi, Razieh Yazdani and Marisol Quintanilla.

They noted that throughout sugar beet-producing states, cyst nematodes have become so prevalent that SBCN impacts 20% to 25% of soil samples collected from sugar beet fields. In heavily infested fields, the nematodes can reduce crop yields by up to 60% and significantly diminish beet sugar content.

The current management strategies for SBCN are similar to other crops: planting tolerant varieties, implementing crop rotation, utilizing cover crops and applying chemical treatments. However, the effectiveness of these methods, especially using nematicides, is limited against established SBCN populations.

The inadequacy of existing control measures highlights the urgent need for innovative and sustainable management approaches, the MSU team stated. They recently evaluated alternative control methods to help develop comprehensive, integrated management strategies that are both effective and environmentally sound.

“By doing so, we can provide farmers with improved tools to manage SBCN infestations, safeguard sugar beet production and ensure the long-term sustainability of this important crop,” they said.

Their study, which took place May 31 – Sept. 1, 2024, had two goals: To quantify the impact of different organic amendments on SBCN population dynamics, and to assess potential yield and sugar content improvements through targeted soil management.

The organic soil amendments tested included Layer Ash Blend (LAB), WormDoo, retail Dairy Doo, high carbon Dairy Doo, Seed Starter 101, Layer Manure and Sili-K, all from Morgan Composting Inc. in Sears, MI.

(LAB is Layer Manure combined with Dairy Doo compost and wood ash. WormDoo is an all-natural soil amendment produced by millions of worms on a worm farm that are fed an organic diet of protein and minerals. Dairy Doo is composted from the manure of dairy cows. Seed Starter 101 is mineral-rich and has mycorrhizal fungi added to aid in germination. Layer Manure is an all-natural soil amendment made from chicken litter sourced from five barns in southwest Michigan. Sili-K is wood ash.)

Also tested were swine manure and poultry manure from the MSU Swine and Poultry Teaching & Research facilities.

The treatments included two different rates – 10 tons/hectare and 20 tons/hectare – of each of the organic amendments. Soil samples were collected 45 days after planting and at harvest. Extracted SBCN cysts, eggs and juveniles were counted to determine population density. In addition, the sugar content in the extracted raw beet juice was measured using a handheld digital refractometer.

Results

The MSU researchers found that among the organic amendments, poultry manure and Layer Manure both significantly increased beet weight compared to non-treated beets across both applications.

As for sugar content, all of the organic amendments – except for poultry manure applied at 10 tons/ha – significantly increased the Brix percentage compared to the untreated control.

(Brix is a measure of the dissolved solids in a liquid, based on its specific gravity. It is commonly used to measure the dissolved sugar content of a solution.)

At 20 tons/ha, poultry manure, retail Dairy Doo, swine manure, WormDoo and LAB significantly increased Brix percentage compared to the non-treated control.

When it came to nematode populations, no significant differences were observed between treatments at either application rate at midseason or at harvest – they all performed relatively well. However, retail Dairy Doo consistently showed the lowest number of SBCN eggs and juveniles at harvest across both application rates.

At the 10 tons/ha rate, all organic amendments except Seed Starter 101 numerically reduced the number of SBCN eggs and juveniles at harvest. Similarly, at 20 tons/ha, all treatments – except WormDoo and high carbon Dairy Doo – reduced SBCN egg and juvenile counts at harvest.

New and innovative treatments for organic growers are always being tested. Check with your Extension agents to see what options may work best for your operation.

by Courtney Llewellyn