TITLE:
Biology of Planococcus citri (Risso) (Hemiptera: Pseudococcidae) on Five Yam Varieties in Storage
AUTHORS:
Emmanuel Asiedu, Jakpasu Victor Kofi Afun, Charles Kwoseh
KEYWORDS:
Planococcous citri, Dioscoreaceae, Dioscorea rotundata, Dioscorea alata, Developmental Period
JOURNAL NAME:
Advances in Entomology,
Vol.2 No.4,
September
17,
2014
ABSTRACT: Yam is an important staple cash crop, which constitutes 53% of total root and tuber consumption in West Africa. It is a cheap source of carbohydrate in the diets of millions of people worldwide and in tropical West Africa. However, attack by Planococcus citri results in shriveling of the tubers, making them become light and unpalatable. They also lose their market value. The total number of eggs laid, incubation period, developmental period and adult longevity of P. citri on stored yam Disocorea species were studied on five yam varieties namely Dioscorea rotundata var. Pona, Dioscorea rotundata var. Labreko, Dioscorea rotundata var. Muchumudu, Disocorea alata var. Matches and Dioscorea rotundata var. Dente in the laboratory with ambient temperatures of 26.0°C - 30.0°C and relative humidity of 70.0% - 75.0%. The mean life spans of the female insect that is from hatch to death on Dioscorea rotundata var. Pona, Dioscorea rotundata var. Labreko, Dioscorea rotundata var. Muchumudu, Disocorea alata var. Matches and Dioscorea rotundata var. Dente were 62.4, 63.5, 66.8, 67.3 and 69.8 days, respectively and those of the male were 23.8, 25.3, 29.6, 30.2 and 33.5 days, respectively. The adult female lived longer than the adult male. The findings showed that citrus mealybug preferred Dioscorea rotundata var. Pona to the rest of the varieties, as it developed faster and laid more eggs (497.0 eggs) on it than on the other varieties. This implies that citrus mealybug multiplies faster and destroys Dioscorea rotundata var. Pona tubers in storage faster than on the other varieties. Therefore, Dioscorea rotundata var. Dente should be the preferred yam for long-term storage.