Evaluation of the effectiveness of alcoholic extract of Launaea mucronata and encapsulated nanoparticles against the mealybug Nipaecoccus viridis on citrus trees

Citrus trees are economically significant, ranking first in global fruit production, with Iraq having a considerable cultivation area of about 140,000 decares. However, citrus trees are prone to various pests that affect their growth and production, such as Nipaecoccus viridis and other insects. Chemical control methods have led to a resurgence of N. viridis in orchards, making eco-friendly approaches crucial. The characteristics and reproduction patterns of N. viridis make its control challenging, and traditional methods are often ineffective. It exhibits high fertility, quick colony formation, and genetic resistance transmission, making its spread concerning. This study focuses on using natural Iraqi environmental extracts, specifically Launaea mucronata, to combat N. viridis. The active compounds in L. mucronata, such as phenols, terpenes, and alkaloids, impact various stages of N. viridis without having negative effects on plants, animals, or humans, aligning with Integrated Pest Management (IPM) programs. We used nanoscale versions of the L. mucronata extract in experiments to see how they affected citrus mealybug eggs, crawlers, and adults at 500 ppm and 1000 ppm concentrations. The results on the eggs showed mortality rates of 43.13% and 66.59% for 500 ppm and 1000 ppm, respectively. As for the crawlers, the mortality rates were 35.78% and 70.17% for 500 ppm and 1000 ppm, respectively. For the adults, the mortality rates were 45.85% and 83.82% for 500 ppm and 1000 ppm, respectively. Statistical analysis indicated significant differences between the two concentrations (eggs, crawlers, and adults), suggesting that the higher concentration is more effective in pest control. Citrus mealybug stages (eggs, crawlers, and adults) were treated with a 2000 ppm concentration of the natural L. mucronata extract in a test tube study. The results showed mortality rates of 52% for eggs compared to 0% in the control group. For crawlers, the mortality rate was 80%, compared to 0% in the control group. As for adults, the mortality rate was 43.3%, compared to 0% in the control group. This indicates that the L. mucronata extract has significant effects on the citrus mealybug stages due to its secondary compounds. In semi-field experiments, we used the nano-Launaea extract after 24, 48, and 72 hours. The results showed relative effectiveness percentages of 93.7%, 86.45%, and 73.58% for adults after 72, 48, and 24 hours, respectively. As for crawlers, the relative effectiveness percentages after the mentioned time periods were 95%, 88.9%, and 76.5%, respectively, showing that nano extracts become more effective over time. In the semi-field experiments with the natural Launaea extract, the relative effectiveness percentages for adults and crawlers after 24 hours were 80.8% and 67.3%, respectively. After 72 hours, the percentages for adults were 29.9% and for crawlers were 11.1%. This suggests that the nano-extracts exhibit higher efficacy compared to the natural extract over time.