Statutory harvest intervals are designed to ensure that residues in harvested fruit are below the maximum residue level (MRL) and not to ensure that levels are so low that residues cannot be detected and reported. Data on available residue degradation for each product / crop combination can be obtained from agrochemical companies and the information used to estimate a suitable pre-harvest application interval likely to produce zero residues.
Information from agrochemical companies or producer co-ops on likely harvest intervals to minimise the risk of reportable residues (RL) in apples for products commonly used post blossom
| Active ingredient | Product example | Statutory harvest interval (days) | Suggested harvest interval (days) to avoid residues |
|---|---|---|---|
| methoxyfenozide | Runner | 14 | 28 |
| penconazole | Topas | 14 | 14 (If 3 sprays only used) |
| thiacloprid | Calypso | 14 | 21 |
| bupirimate | Nimrod | 14 | 14 |
| captan | Captan 80 | 14 | ? |
| codling moth granulovirus | Carpovirusine, Cyd-X, Madex Top | 0 | Not applicable. No recordable residue |
Adopting this approach alone and extending the harvest interval to ensure that any possible residues have declined to zero by harvest will reduce the incidence of residues, but complete elimination cannot be guaranteed as the retention of residues is very much affected by seasonal weather conditions. In addition, consideration has to be given to alternative ways of controlling the pest and disease problems that the late season product sprays were targeted against.