Abstract:
A study was conducted to evaluate the efficacy of an insecticide (deltamethrin) incorporated bags (Zerofly®) against the insect
attacks during paddy storage under Sri Lankan conditions. The study was conducted at Institute of Post Harvest Technology
(IPHT), Anuradhapura andat the warehouse of Paddy Marketing Board (PMB), Anuradhapura. Paddy sample in Zerofly® sacks
were stacked at both locations and for controls, untreated polysack bags were used.Paddy samples that were collected before
storage and at monthly intervals during the storage period were analysed for moisture content, weight loss due to insect damages,
Thousand Grain Mass (TGM), germination percentage, Total Milling Yield (TMY) and Head Rice Yield (HRY). Data was
analyzed using Analysis of Variance (ANOVA) by Statistical Analysis System (SAS). The moisture content of paddy grains
fluctuated between 13.3 – 14.3% during storage period but any significant difference was not observed among bag types. The
level of insect damages in control was increased with storage time while the initial level of insect damage of treated bags
remained unchanged.The mass loss due to insect damagesof grains was significantly higher (p=0.05) in untreated bags than
treated bags. The insect damage was reduced by 3.5-4.a% using Zerofly® bags during paddy storage. In addition, dead insect
bodies were found onouter surface of the insecticide incorporated bags but no live or dead insects were found on untreated bag
surface during storage. Mainly rice weevil (Sitophils oryza) and lesser grain borer (Rhysoperthadominica) were found in paddy
samples of untreated bags and number of insects increased with time. The germination percentage of grains in untreated bags was
significantly higher than to thecontrol. It was reduced from 93% to 60-64% and 93% to 82-83% in control and treated bags
respectively.During the six months of storage, TGM did not show any significant difference (p=0.05) among different treatments.
TMY and HRY resulted significantly (p=0.05) lower values of paddy stored in untreated bags than Zerofly® bags. Use of
insecticide incorporated bags can reduce the loss of TMY and HRY of paddy during storage. The study revealed that insecticide
treated bags are an appropriate packaging material to protect stored paddy from insect infestations under Sri Lankan conditions.
