ARS | Publication request: The effects of composted insect rearing waste on radish, squash and green bean

Submitted to: Compost Science and Utilization
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: February 1, 2012
Publication Date: June 1, 2012
Citation: Reed, S.T., Epsky, N.D., Heath, R.R., Joseph, R. 2012. The effects of composted insect rearing waste on radish, squash and green bean. Compost Science and Utilization. 20(2):87-91.

Interpretive Summary: Nutrient analysis revealed low amount of P and Ca in colony waste. Nitrogen, K, Mg, Zn, Fe and Cu contents were high enough to support optimum plant growth for at least one growing season. Shoot dry weights of radish plants grown in 80:20, 60:40 and 40:60 CW:CP were higher than the ones produced with the commercial mix. Root dry weights were highest in the 80:20 CW:CP treatment. Overall, radish plants grown in 60:40 and 80:20 CW:CP mixtures performed best. Shoot and root dry weights were higher in squash plants grown in 50:50 and 20:80 CW:S ratios. Both shoot and root dry weights were highest in the 20:80 CW:S treatment. No substance in the CW appeared to be detrimental to plant growth. As a potting substrate, CW additions of between 30 and 70% to equal amounts of compost plus peat resulted in plant performance greater than or equal to a commercial mix. Plants grown in unfertilized CW mixtures out performed those grown in a fertilized peat/sand mixture. Composted insect colony waste is a nutrient rich material that can be used as part of a growth substrate mix for potted plants.

Technical Abstract: A study was initiated to determine the potential for composted solid and semi-solid insect rearing waste as a growth substrate for plants. Semi-solid larval diet was washed through the vermiculite substrate used for larval transformation to pupa. The resulting material was composted for six weeks. Radish (Raphanus sativus L.) was grown in either a commercial potting mixture or in blends of colony waste (CW) and equal parts compost plus peat (CP). Squash was grown in different CW:sand (S) mixtures and green bean grown in a 50:50 CW:S mix with different levels of fertilization. Mixes of 80:20 and 100:0 CW:CP had radish germination rates equal to the commercial mix. Radish shoot dry weight from 80, 60 and 40% CW were higher than the commercial mix. Squash grown in 20% CW had the highest shoot and root dry weights. No substance in the CW appeared to be detrimental to plant growth. As a potting substrate there were no differences in plant performance among the CW, the commercial mix or the CP.