A Pest Risk Management Tool

Managing pest risk in peanut can be complicated and is very important to maintaining a successful and sustainable peanut production system. A pest risk management tool has been developed to support farmers and their advisors in Malawi assess the risk of reduced yield or greater aflatoxin contamination. The risk tool allows users to determine if the production plan they have developed effectively minimizes yield lost to pests or other stresses. An action that may reduce risk in one way might cause a problem in another area.

The risk tool for Malawi considers the following practices:

• Planting date

• Land preparation

• Plant density

• Aphid spray

• Seed inoculant

• Fungicide Variety

• Gypsum

• Crop rotation

• Digging date

• Fertilizer

• Drying

• Soil pH

• Storing

To access the risk tool, follow the following steps.

1. Go to the website: https://davidjordan.wordpress.ncsu.edu/resources/.

2. Select Malawi and follow the screen commands.

3. Input data in all sections on the left side of the screen (see Figures 10.1, 10.2. and 10.3 for examples).

4. Consider the risk as shown in the red, yellow and green dots. The number of red, yellow, or green dots on the right side of the screen indicates the risk level to groundnut yield and contamination by aflatoxin.

5. If needed, change practices to minimize risk, but keep in mind that risk of other pests can be affected and that production costs will also change.

6. Remember the risk tool is for planning prior to the season. Almost all farmers start with a plan but need to make adjustments based on weather, pest outbreaks, and economic constraints. This risk tool was created to help farmers start the season by selecting practices that minimize pest risk and identify pests that might impact peanut yield during the season. The risk tool is currently being updated to reflect new varieties, production and pest management practices, and to include a weed management category.

Examples of Risk to Groundnut Yield and Aflatoxin Contamination

The risk tool assigns a range of points to a production or pest management practice in the field that affects groundnut yield and aflatoxin contamination. The tool also includes risk of aflatoxin contamination after harvest during drying and storing. The range of points is presented in Figures 10.1 and 10.2. The extremes of risk are presented in Figures 10.3 and 10.4. When a farmer follows agronomic and pest management practices that are not effective in optimizing yield, the harvest likely will be small (Table 10.3). While groundnut volume coming out of the field may be low, choosing a poor digging date and following poor drying and storage practices can also affect aflatoxin contamination. In the scenario associated with Figure 10.3, the farmer needs to change many of the production and pest management practices, as well as his approach to drying and storage, in order to produce and deliver high quality and safe groundnuts to the marketplace. It is obvious that smallholder farmers may not have access to all technologies that could protect yield and minimize aflatoxin contamination. However, there are some steps in the field and after harvest that could improve production.

The most effective approach to protect yield and minimize aflatoxin contamination is presented in Figure 10.4. It is unlikely all farmers can implement the best management practice at each step. However, farmers should strive to create a production scenario and a complementary post-harvest strategy based on a reasonable number of elements presented in Figure 10.4.

Three realistic examples are presented in Figures 10.5, 10.6, and 10.7. In one example, a leaf spot-tolerant variety is planted and one extra weeding is employed. Post-harvest, groundnuts are dried on a tarp to minimize aflatoxin contamination (Figure 10.5). However, this approach is hampered by the late planting date which 42 endangers both yield and food safety because of aflatoxin. If the risk tool was used in planning, the farmer would be able to see that planting date is a critical factor and that he should do everything within reason to plant earlier in the season.

In the second example (Figure 10.6), the farmer chooses a late planting date, but employs other elements of production and pest management to protect yield. Fertilizer is applied, soil pH is higher, weed control is increased and digging occurs at the optimum timing. After harvest, pods are dried in a way that protects them from soil contamination and prevents cycles of wetting and drying. The groundnuts are dried to the optimum moisture level and stored in sealed bags. Even though this approach appears to protect yield and minimize aflatoxin contamination, considerable risk remains because of the likelihood that the dry season will return before the crop is mature.

In the final example (Figure 10.7), groundnuts are sown in early December rather than early February. This resulted in a reduction in risk to yield and food safety through a reduction in risk of aflatoxin contamination. In all five examples, the farmer and agronomists who are making recommendations can assess the relative cost of practices. Financial constraints can limit what inputs can be used to protect yield and minimize contamination with aflatoxin. The risk tool provides an avenue to analyze the benefits and costs associated with a production package in a comprehensive manner that can potential minimize risk to both yield and food safety through aflatoxin mitigation.