Assessment on Weight Loss of Maize Seeds (Jibat Variety) Caused by Maize Weevil (Sitophilus Zeamais Motsch.) (Coleoptera: Curculionidae) after Treated by Botanical Powder under Laboratory Condition

Weight Loss

The maize seeds (Jibat variety) were used 40-120 days after introduction of weevils with botanical treatments in order to check / estimate the maize weight loss. The experiment was used to assess weight loss assessment after 40, 80 & 120 days of application. The extent of maize damage was assessed by counting the whole grains from each jar. The number of damaged (grains with characteristic hole) and undamaged grains was counted and weighed. The percentage damage (PD) of the weevils to the grains was calculated using the methods of Adedire and Ajayi [7] and Fatope, et al. [8] respectively.

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Where, U= weight of undamaged fraction in nth sample, N= total number of grains in a sample, Ua= average weight of undamaged kernel, D= weight of damaged fraction in nth sample.

Data collected

After the treatment application, weight loss (40, 80 and 120 days) was recorded from the treated botanical, malathion 5% dust and untreated control.

Experimental Design and Treatments

Completely randomized design (CRD) with three replications was used in factorial arrangement in maize weight loss after exposed to weevil. The number of treatments is 22 and the total number of treatments was sixty six (66) including standard check and untreated or control.

Weight loss

Results on the assessment indicated that high weight loss due to the infestation of S. zeamais in a treated and untreated seeds was recorded (Table I). All botanical powders significantly (P< 0.05) reduced the weight loss when compared to the untreated control, 40 days after application. The percent weight loss ranged from one to four percent in all tested botanicals. Significant loss was recorded from doses of 8 & 11% (w/w) applied. However, lower weight loss was recorded at higher doses of (8% to 11 % w/w) 40 days after application. There was no maize seed weight loss recorded on maze seeds treated with malathion 5% dust. However, up to 50.02 % recorded in untreated control after 40 days of application. The same trend of results was observed 80 days after application of the different botanicals.

Eighty days after application, all botanical powders significantly (P< 0.05) reduced the weight loss when compared to the untreated control. The percent weight loss ranged Justica schrimperiana (14.67 %) at 2% dose and Calpurnia aurea (3.33%) at 2% dose treated maize seed. There was no weight loss recorded from maize seeds treated with Malathion 5% dust. However, up to 258.33% fold weight loss was recorded from the untreated control (Table 1).

One hundred twenty days after application; lower weight loss was recorded maize seed treated with botanicals, no weight loss was recorded seed treated with Malathion 5% dust. But lower weight loss was registered seed treated with other botanicals when compared with untreated control which recovered up to 300.79% fold of seed loss.

also indicated that storage losses of maize range from 25- 33% in western zone. An annual average of 20-30% of this little grain is then lost through damage by maize weevil in storage [11]. Damage to grain caused by this weevil includes reduction in nutritional value, germination, weight and commercial value [12].

Different report findings showed that grain losses ranging from 20-90% have been reported for untreated maize due to S. zeamais attack [9]. Legesse and Asfaw [10]

Means followed by different letters are significantly (p˂ 0.05%) different using Tukey’s Studentized Range (HSD). Table 1: Percent cumulative weight loss of maize seed after application of Different botanical.