To begin, select fallen, overripe, or ripe fruit with signs of damage, over position scars and soft spots. Cut the fruit into large pieces and place them into a four-liter Ziploc storage bag. Add water to the bag until the water covers the chopped fruit by 25 to 50 millimeters.
Squeeze the fruit gently by hand until all the pulp has dislodged from the peel and has a smooth consistency. Use large sieves to process around five fruits at once. Stack the sieve with a large mesh sieve atop a small mesh sieve, and place a third sieve on the bottom of the stack to detect early instars.
Pour the pulp into the top sieve, and thoroughly wash the pulp through the stack of sieves using water from a hose, faucet or a bottle until the fine pulp has passed through the sieves. Visually scan the top sieves for late instar larvae that might have been retained with the peel or any large pieces of fruit. And carefully inspect the second sieve for late instar larvae.
Collect larvae from the sieves with larval forceps and place them into vials with 70%ethanol. Premix the sugar solution by dissolving 453 grams of dark brown sugar in two liters of tap water. Wash the pulp from the finer mesh sieves to the edge of the sieve with tap water, and then move the material to an 11-liter plastic dish pan.
Add the brown sugar solution until it covers the pulp by 25 to 50 millimeters, and add two drops of anti-foamer. After five minutes, collect larvae that float to the surface of the solution with larval forceps into vials with 70%ethanol. Label a vial with the collection location, date, type of fruit, and collector for later examination and identification.
The mean number of Anastrepha suspensa larvae and the mean number of larvae collected per minute from five guavas and processed by cutting and by mushing, sieving and floating or MSF method are shown here. The result shows that the MSF method yielded greater numbers of larvae and more larvae per minute than hand cutting. This MSF method was validated using manual infestation of mango and papaya to simulate low Bactrocera dorsalis infestation.
More larvae were found using the MSF method for both papaya and mango when compared to the fruit cutting method. For both mangoes and papayas, the full MSF method resulted in higher numbers of larval detections and was faster than fruit cutting.
