Neemazal, a biopesticide containing 47.25% azadirachtin, was assessed for its impact on the haemolymph and haemocyte profile of Periplaneta americana. This study examined variations in the Total Haemocyte Count (THC), Differential Haemocyte Count (DHC), and blood volume in both male and female cockroaches after exposure to different doses of Neemazal (3, 5, 7, and 12 µL) at specific post-treatment-periods (PTPs) of 10, 30, 60, and 120 minutes.
The THCs recorded for female cockroaches at the 10-minute PTP were 6172.8±0.75, 6163.0±1.54, 6162.2±1.66, 6160.8±1.66, and 6158.8±1.31/mm³ for doses of 3, 5, 7, 10, and 12 µL, respectively. In males, the corresponding THC values were 6192.4±2.05, 6189.2±1.66, 6184.2±1.24, 6181.5±1.28, and 6176.8±1.24/mm³. Similar trends were observed across the other PTPs. Neemazal exposure led to a dose-dependent decrease in the THC in both sexes compared to that in the control group.
For the treatment with 3 µL and the 10-minute PTP, the DHCs found in female cockroaches were 19, 59.2, 40.2, 27.6, and 30.8%; in male cockroaches, these were 18, 52, 40.4, 28, and 20.8%. Prohaemocytes, plasmatocytes, granulocytes, oenocytes, and coagulocytes were observed, which indicated a decrease in haemocytes as compared to the controls. The DHC analysis revealed an initial decline within 10 minutes post-treatment, followed by a partial recovery, though these values remained consistently lower than those for the controls in all PTPs.
The blood volume changes observed for the 3 µL dose were 35.36±0.0014, 29.48±0.0013, 25.34±0.0023, and 30.71±0.0014 at 10, 30, 60, and 120 minutes, respectively. Similar trends were noted across the different doses and PTPs. Overall, blood volume exhibited a progressive, dose-dependent decrease across all of the PTPs.
The statistical analysis revealed significant changes in all of the parameters measured in the treated groups compared to those in the controls, with p-values of p<0.005, p<0.01, and p<0.02. These findings suggest that Neemazal disrupts the haemocyte dynamics and haemolymph homeostasis in P. americana, indicating that its potential mode of action involves impairing its immune and circulatory functions.
