Host stage preference and parasitism behaviour of Aenasius bambawalei an encyrtid parasitoid of Phenacoccus solenopsis

Publication Type

Journal Article

Journal Name

Journal of Horticultural Science

Publication Date

1-1-1996

Abstract

Effect of natural chilling and artificial chilling durations of 2-8 weeks at 9°C on percentage bolting and flowering and on days taken from planting to the two events in carrot cv. Nantes was observed at four locations in Kenya in 1991/92. These were; Juja (1500 m above sea level in a warm Upper Midland (UM) zone) and Molo (2454 m), Kinangop (2558 m) and Marindas (2804 m), all in an Upper Highland (UH) zone. The observation was repeated in 1992/93 but in Juja and Kinangop only. In 1991/92 the lowest bolting and flowering percentage (<25%) was recorded in carrot plants whose stecklings had received natural chilling at all planted sites while in those whose stecklings had received artificial chilling, bolting and flowering percentage increased with artificial chilling durations within each location. Over 75% flowering was obtained only in those plants grown from carrot stecklings chilled for six and eight weeks within each location and in those given four weeks chilling at Kinangop. In 1992/93, the results were quite opposite from those of the previous year at Kinangop when 100%, bolting and flowering was obtained in all chilling treatments including the naturally chilled plants. But at Juja bolting and flowering in 1992/93 was similar to the previous year. Days from planting to 50% of final bolting and flowering decreased with increased durations of chilling at all sites, in both years. Days to final bolting and flowering followed a similar pattern. The control plants bolted and flowered earlier than those given two weeks of chilling in 1991/92 and at the Kinangop site in 1992/93. Significant differences (P<0.05) in days taken to bolting and flowering were observed between locations especially in 1992/93 when Juja plants bolted significantly earlier than those at Kinangop in most treatments.

Link to Full Text

Share

COinS