In many perennial fruit systems, unharvested fruit left on the orchard floor can exacerbate insect pest problems by harbouring insect pest larvae, according to a paper in Organic Agriculture.

Krista A. Buehrer and Matthew J. Grieshop report that apple, cherry and pear growers in the northeastern USA must control a number of challenging insect pests, including plum curculio (Conotrachelus nenuphar Herbst), codling moth (Cydia pomonella L.), and oriental fruit moth (Grapholita molesta Busck).

Integrating livestock into tree fruit systems for the purpose of consuming leftover fruit may provide insect and weed pest management services.

The authors rotationally grazed pigs after harvest in certified organic apple, cherry and pear orchards to determine the amount of fruit the hogs would consume from the orchard floor, the impact hogs would have on orchard ground cover, and what pest insects the hogs could potentially suppress by consuming leftover fruit.

The pigs consumed 100 per cent of leftover fruit in all three orchard types.

Pigs significantly increased the amount of bare ground and decreased the amount of grass in all three orchard types.

Both codling moth and oriental fruit moth larvae were found to be present in leftover apples and pears collected from the ground, whereas no pest insects were found in leftover cherries.

Plum curculio fruit damage was significantly lower in grazed cherry plots, and codling moth/oriental fruit moth fruit damage was significantly lower in grazed pear plots following the first year of the study, concluded Buehrer and Grieshop.

Fruit damage data could not be collected following the second year of the study due to total crop loss.

Reference

Krista A. Buehrer and M.J. Grieshop. 2014. Postharvest grazing of hogs in organic fruit orchards for weed, fruit, and insect pest management. Organic Agriculture. 4(3):223-232.

November 2014