The effects of Empoasca dolichi Paoli (Hemiptera: Cicadellidae) on the performance and yield of two cowpea cultivars

Abstract

The effects of feeding by groups of 0, 15, 30, 45, 60, 75 or 90 adults of Empoasca dolichi Paoli per plant on the growth and yield of caged Prima and Ife Brown cowpea plants infested 14, 21 or 28 days after planting were studied in Ibadan, Nigeria. Caging had no significant adverse effects on yield. E. dolichi caused severe hopper-burn in plants infested 14 days after planting. The mean pre-flower-opening stage lasted 42-1, 38-0 and 39-0 days in Prima and 446, 407 and 423 days in Ife Brown plants infested 14, 21 and 28 days after planting, respectively, the first figure for each cultivar being significantly different from the other two. The mean yields were 23 3, 28 5 and 298 pods per plant for Prima, and 350, 48-1 and 437 for Ife Brown, respectively, the first figure for each cultivar being significantly lower than the other two. The reduction in seed yield in damaged plants infested 14 days after planting ranged from 287 to 413% for Prima and 272 to 56-9% for Ife Brown, the reductions being significantly correlated with scores for feeding damage by E. dolichi.

Effect of Weeds on Pre-flowering Insect Infestation and Seed Yield of Cowpea (Vigna unguiculata) in a Rainforest Area of Nigeria

“…Feeding experiments have shown that 8, 17, 35 and 38 O. mutabilis adults per plant caused 50% yield loss on one-, two-, three-and four-week-old plants, respectively (Raheja, 1981). However, Parh (1983) demonstrated that plants of two cowpea varieties attacked by high leaf-hopper populations (90 adults per plant) did not suffer significant losses in seed yield. It is possible that leafhopper numbers in this study were too few to cause damage.…”

True Parthenogenesis and Female-Biased Sex Ratios in Cicadomorpha and Fulgoromorpha (Hemiptera, Auchenorrhyncha)

“…In Europe, the genus Empoasca contains many pests of crops and, therefore, is widely studied (e.g., [96][97][98][99]); in spite of this, other cases of asexual reproduction have not been known. It is worth mentioning, however, that Parh [100], during an investigation of the Empoasca complex associated with cowpea crops Vigna unguiculate (Linnaeus, 1759), Van Eselt (Fabales, Fabaceae), in Nigeria, observed the presence of "less harmful unidentified parthenogenetic females" in addition to the main pest species, Empoasca dolichi Paoli, 1930, a. Akingbohungbe [101] speculated that it might have been Empoasca confusania Ghauri, 1979, because its terminalia matched those of females of this species and, to a lesser extent, the terminalia of E. dolichi. Although both E. dolichi and E. confusania coexist on cowpea with the parthenogenetic form in southeastern Nigeria, rearing experiments proved that they both reproduced sexually [102].…”