Wednesday, November 7, 2007
245-22

Converting Insect Colony Waste into a Potting Substrate.

Stewart Reed, Nancy Epsky, Robert Heath, and Ricardo Joseph. USDA-ARS, 2028 Southeast 23 ave., Homestead, FL 33035

Rearing insect generates both a solid and semisolid waste that is generally discarded in landfills. A study was initiated to determine if the semi-solid insect colony waste product and vermiculite used in insect rearing could be combined and used as a growth substrate for plants. The semi-solid larval diet was wash through the vermiculite used to line cages. The resulting material was drained and air dried for approximately seven days. This material was tested as a potting substrate in two studies. In the first study radish (Raphanus sativus L.) was grown in either a commercial potting mixture, 100% colony waste (CW), 100% equal parts compost plus peat, and 80%, 60%, 40% or 20% CW with equal parts compost and peat for a total of 70 pots. In the second study squash was grown in CW:sand in ratios of 0:100, 20:80, 30:70, 50:50, 70:30, 80:20 and 100:0. Colony waste mixes of 80% and 100% had radish germination rates equal to that of both the commercial potting mix and 100% peat/compost (0%CW). Radish plants grown in CW/compost/peat mixtures of 80%, 60% and 40% CW resulted in shoot dry weights higher than that produced in the commercial mix and significantly higher than the 100%, 20% and 0% CW. Squash plants grown in 20:80, 50:50 and 30:70 CW:S developed more nodes than those grown in only sand (0:100 CW:S). Both shoot and root dry weights for squash were highest in the 20:80 CW:S ratio treatment. No substance in the CW appeared to be detrimental to plant growth. As a potting substrate there were no differences in plant performance between the CW, the commercial mix or a peat:compost mix.