Using Surround for Managing Apple Maggot?

Readers of the ONNL know that Surround WP Crop Protectant (kaolin clay) has been registered for the broad spectrum suppression of several key insect pests in pome fruit, including pear psylla, tarnished plant bug, leafrollers, apple maggot, and plum curculio, among others. John Gardner, Apple Specialist and co-editor of the ONNL, has written several articles on the merits of using this product as a protectant against sunburn and heat stress. We anticipate label expansions for Surround in other crops within the next few years.

Trials conducted in Ontario in 2001 and 2002 indicate that this product is an effective tool for limiting damage caused by the apple maggot. For a summary of results, see the Surround® WP Crop Protectant in Ontario Apples - Report on 2002 Field Trials

Surround does not work in the same manner as insecticides. Growers using Surround for managing apple maggot need to keep in mind that this product works by forming a barrier between the fruit and the pest: Maintaining adequate coverage during pest activity periods is critical.

What constitutes "adequate coverage"? Fruit should have a uniform, hazy whitewashed appearance, with the developing colour still evident under the coating. Growers often question the need for re-application following a rain event. We have found that a light rain may actually help to redistribute the product on the surface of the fruit; at any rate, you must wait until the foliage and fruit are dry before determining the need for re-application. Heavy rainfall, new growth and wind erosion can affect the coverage.

Figure 1. Insufficient coverage.

Figure 2. (More than) Sufficient coverage.

Apple maggot overwinters in the soil as pupae. Since adult emergence and activity runs from late June through September (peaking in August), this means that Surround coverage must be maintained until quite late in the season. Keep in mind that emergence is closely linked to soil moisture levels. In dry years the apple maggot pupae may actually remain in the soil until the following growing season. In 2004, lack of soil moisture is likely NOT an issue for the development and emergence of apple maggot – make sure to monitor for this pest as part of your IPM program!

NOTE: Washing will be required where this product is used in the management of late season pests. Most residues are readily removed with packing line brushes and forced water sprays, coupled with approved washing detergents. However, some residues may still be evident in the calyx and stem ends, particularly with red-skinned varieties. The use of waxes can improve fruit appearance, in this case. Speak to the packer regarding the use of this product near harvest, as waxing is not accepted for fruit destined to certain markets.

Related Links

• Apple Maggot
• Managing Apple Maggot
  
• Surround® WP Crop Protectant in Ontario Apples - Report on 2002 Field Trials