Sugar flotation procedures have been used for many years to separate insects from soil and other substrates. In this study we investigated whether brown sugar flotation (BSF) could be used for detecting eggs and larvae of Bactrocera tryoni (Froggatt) and Ceratitis capitata (Wiedemann) in cherries. Our first study involved both species and combined BSF with either manually or mechanically crushed fruit to quantify the egg and larval detection ability of BSF in conjunction with these sample preparation methods. A second set of experiments (using B. tryoni only) focused on determining the sensitivity of BSF for detecting fruit fly infestation and determining the proportions of different life stages recoverable. This was done by varying oviposition periods to generate fruits with different infestation levels. Our final experiments were used to develop an optimized cherry fruit sampling regime for detecting B. tryoni using BSF. Wet sieving/maceration of the fruit residue and incubation of the macerated fruit sample to allow further insect development were used to determine the number of eggs and larvae in each test sample that were not detected using BSF. Our results show that BSF is more effective when combined with mechanical (rather than manual) fruit crushing. BSF is highly sensitive, detecting at least one B. tryoni second instar from all the samples tested down to a pest density of 1–5 larvae in one fruit within a 35-fruit sample. BSF was less sensitive for egg detection, however when 6 or more eggs were present within a sample of 35 fruits, the probability of detecting at least one egg was ≥85%. Samples of 35 or 42 cherries provided a higher probability of detecting B. tryoni than larger samples when 1–5 eggs or larvae were present in total. BSF is an effective tool for detecting the presence of fruit fly eggs and particularly larvae in cherries and should be considered for incorporation into the current market access protocol for minimizing fruit fly risk in Australian cherry exports.

多年来一直使用糖浮选程序将昆虫与土壤和其他基质分离。在这项研究中，我们研究了红糖浮选 (BSF) 是否可用于检测樱桃中的Bactrocera tryoni (Froggatt) 和Ceratitis capitala (Wiedemann) 的卵和幼虫。我们的第一项研究涉及物种并将 BSF 与手动或机械压碎的水果相结合，以结合这些样品制备方法量化 BSF 的卵和幼虫检测能力。第二组实验（使用B. tryoni仅）重点确定 BSF 检测果蝇侵染的敏感性并确定可恢复的不同生命阶段的比例。这是通过不同的产卵期产生具有不同侵染水平的果实来完成的。我们的最终实验用于开发优化的樱桃果实采样方案，用于使用 BSF检测B. tryoni。水果残渣的湿筛分/浸渍和浸渍水果样品的孵育以允许进一步的昆虫发育用于确定每个测试样品中未使用 BSF 检测到的卵和幼虫的数量。我们的结果表明，BSF 与机械（而不是手动）水果压碎相结合时更有效。BSF 高度灵敏，可检测至少一种B. tryoni在 35 个水果样品中的一个水果中，从所有测试的样品中的二龄到害虫密度为 1-5 个幼虫。BSF 对鸡蛋检测的敏感性较低，但是当 35 个水果样本中存在 6 个或更多鸡蛋时，检测到至少一个鸡蛋的概率≥85%。当总共存在 1-5 个卵或幼虫时，35 或 42 个樱桃的样本比更大的样本提供了更高的检测B.tryoni 的可能性。BSF 是检测果蝇卵，尤其是樱桃中是否存在幼虫的有效工具，应考虑将其纳入当前的市场准入协议，以最大程度地降低澳大利亚樱桃出口中的果蝇风险。