Effect of planting dates on the population dynamics of Cylas puncticollis and sweet potato storage roots damage in South Western Cameroon

The sweetpotato Ipomoea batatas L. (Convolvulaceae) is one of the most important food crops in Africa and the world. The weevil, Cylas puncticollis (Fabricius), is the most destructive field and storage insect pest of sweet potato in Africa. Because of the cryptic feeding nature of the very destructive larval stages, chemical control is often not effective. A field study was therefore designed to determine the effects of different planting dates on infestation and damage of various sweet potato cultivars by the weevils in South Western Cameroon. Ten sweet potato cultivars were planted in different months i.e April and July for the wet season and October and January for the dry season in 2012 and 2013. The vines and storage roots were observed for C. puncticollis damage. Results showed a significance difference on the percentage infestation and yield (P< 0.05) amongst the various planting periods with the least infestation registered for the July (0.3%) while the highest infestation was realized in the January planting (9.22%). The highest yield was obtained from the April planting (7.22 tons/Ha) and the lowest was recorded for the October planting (4.92 tons/Ha). Differences in vine damage amongst the planting periods were not significant at (P > 0.05). Delayed harvesting during the rainy season led to only slight (9.1%) increase in C. puncticollis infestation at 135 DAP while the infestation was high during the dry season at harvest and further increased as harvesting was delayed more than 90 DAP. Sex ratio of weevils throughout the wet and dry seasons showed a higher ratio of females.Key words: Sweetpotato Cylas puncticollis, Planting dates, Percentage infestation

Efficacy and Tolerability of Malartin and Sulphadoxine-Pyrimethamine Combination against Uncomplicated Falciparum Malaria in Dibanda, Southwest Cameroon

Artemisinin derivatives are now the most potent and rapidly acting antimalarials. The aim of this study was to assess the in vivo efficacy and tolerability of a combination of Malartin (an artesunate) and sulphadoxine-pyrimethamine (SP) in the treatment of uncomplicated falciparum malaria in Dibanda, Cameroon. A total of 197 subjects were recruited into the study and administered Malartin for 3 days and SP as a single dose on day 0. Only 174 of the subjects were successfully followed up on days 3, 7, and 14. The overall success rate of the drug combination was 92.53%. Parasite density decreased during the follow-up period in different age groups, sexes, and social classes. The prevalence of anaemia decreased from 22.99% at enrolment to 9.77% on day 14, and the difference was significant (P < 0.05) on all days of followup. The drug combination did not give rise to any serious side effects

Environmental Factors Affecting Malaria Parasite Prevalence in Rural Bolifamba, South- West Cameroon

The impact of some environmental factors on malaria parasite prevalence was investigated in rural Bolifamba, Cameroon. The study population comprised 1454 subjects aged 0 \u2013 65 years. Malaria parasite prevalence was higher in the rainy (50.1%) than in the dry season (44.2%) with a significant difference (P=0.001) in mean parasite density between seasons. Individuals &lt;15 years old, had significantly higher malaria parasite prevalence (55.5%) than those &gt;15 years (37.4%). Malaria parasite prevalence (P=0.001) and parasite density (P=0.03) were higher in the individuals of wooden plank houses than those of cement brick houses. Inhabitants of houses surrounded by bushes or garbage heaps and swamps or stagnant water showed higher malaria parasite prevalence and densities compared with those from cleaner surroundings. Anopheles gambiae (63.8%) and A. funestus (32.8%) were associated with perennial transmission of malaria. Our data indicates that poor environmental sanitation and housing conditions may be significant risk factors for malaria parasite burden in Bolifamba

Effects of climate variability on insect pests of cabbage: adapting alternative planting dates and cropping pattern as control measures

Abstract Background Considering the potential impact of climate change on the ecology of insect pests, different planting dates and cropping patterns were investigated as farm-level adaption to control insect pests of cabbage and improve productivity. Methods This is a 3 × 4 factorial experiment setup in randomized complete block design including three planting dates (early, normal and late) and four cropping patterns (control—sole cabbage or tomato, tomato intercrop, Piper emulsion and insecticide) with four replications each. Results Cabbage infestation ranged from 1 to 29 and correlated negatively with planting dates or treatments, which differed (P < 0.001) significantly across planting dates, treatments and their interaction, with the highest during early planting. Diamondback moth larvae correlated negatively with planting dates or treatments, ranging from 0 to 13 that differed significantly (P < 0.001) across planting dates, treatments and their interaction. Looper larvae correlated negatively with treatments, ranging from 0 to 8 that differed significantly (P < 0.001) across planting dates, treatments and their interaction, with highest during normal planting and lowest during late planting. Webworm larvae correlated negatively with planting dates or treatments, ranging from 0 to 13 that differed significantly (P < 0.001) across planting dates, treatments and their interaction. The number of sprouted plants ranged from 0 to 6 and differed significantly (P < 0.001) across planting dates, treatments and their interaction, with the highest in early planting for control that differed significantly from late planting. Cabbage yield correlated positively with planting dates and ranged from 2.8 to 6.0 tons per hectare that differed significantly (P < 0.001) across planting dates, treatments and their interaction, with the highest during normal and late planting dates. Conclusion The interaction of planting dates and Piper emulsion or intercropping treatments can be effectively used as control measure for insect pests of cabbage leading to greater yield, with late planting as viable farm-level adaptation to climate variability

Extracts of tropical African spices are active against Plutella xylostella

Extracts from Piper guineense, Aframomum melegueta, Aframomum citratum and Afrostyrax kamerunensis were investigated for their antifeedant, lethal and developmental effects against Plutella xylostella larvae through laboratory dual-choice tests and topical application. Water and ethanol extracts of P. guineense were dose-dependent antifeedants at concentrations ≥300 and 500 ppm, respectively, whilst methanol extracts required ≥1,000 ppm. Methanol and hexane extracts of A. melegueta acted at ≥100 ppm and water extracts at ≥300 ppm, but ethanol extracts were deterring feeding only slightly at ≥1,000 ppm. Hexane and methanol extracts of A. citratum inhibited feeding at ≥300 ppm and water extracts did so at ≥500 ppm. None of the Afrostyrax kamerunensis extracts deterred feeding at any of the concentrations tested. No mortality was observed at any of the concentrations after topical application of the extracts on the larvae. However, the effects on larval development varied with extract concentration and larval age. Ingestion of the water and ethanol extracts of P. guineense caused 100% mortality of second instars at ≥100 ppm two to three days after infestation (DAI). Methanol and water extracts of A. melegueta and A. citratum, respectively, achieved ≥80% mortality of larvae at concentrations of ≥500 ppm and ≥1,000 ppm, respectively. With third instars, the mortalities were significantly lower; however, the P. guineense water or ethanol extracts caused 100% mortality two to four DAI. Larvae that survived till pupation had significantly longer larval periods compared with the control after application of A. melegueta extracts. We concluded that potent extracts from Aframomum melegueta, Aframomum citratum and especially P. guineense could be used as complementary measures in the management of P. xylostella by subsistence farmers

A new species of Zoraptera, Zorotypus komatsui sp. nov. from Cameroon and a redescription of Zorotypus vinsoni Paulian, 1951 (Polyneoptera, Zoraptera)

A new species of the order Zoraptera, Zorotypus komatsui Matsumura, Maruyama, Ntonifor & Beutel, sp. nov., is described from Cameroon. The female and male morphology of another species, Z. vinsoni, is re-described, and its new distribution in Madagascar is recorded. A particular focus is on the male postabdominal morphology. This is apparently a crucial body region in the very small order with an extreme variation of the genital apparatus but otherwise a very uniform morphology. The male of the newly described species shares rudimentary male genitalia and well-developed postabdominal projections with the distantly related Spermozoros impolitus, apparently a result of parallel evolution. Whether males of Z. komatsui also perform external sperm transfer like S. impolitus remains to be shown. The collecting of the material used for this study suggests that the present knowledge of zorapteran species diversity of the Afrotropical region is very fragmentary

Studies on aspects of the bionomics and pest status of Piezotrachelus varius Wagner (Coleoptera: curculionidae) on cowpea (Vigna unguiculata (L) walp in the Western derived savanna zone of Cameroon

No Abstract. Journal of the Cameroon Academy of Sciences Vol. 5(2&3) 2005: 101-10

Clinical Study Efficacy and Tolerability of Malartin and Sulphadoxine-Pyrimethamine Combination against Uncomplicated Falciparum Malaria in Dibanda, Southwest Cameroon

Artemisinin derivatives are now the most potent and rapidly acting antimalarials. The aim of this study was to assess the in vivo efficacy and tolerability of a combination of Malartin (an artesunate) and sulphadoxine-pyrimethamine (SP) in the treatment of uncomplicated falciparum malaria in Dibanda, Cameroon. A total of 197 subjects were recruited into the study and administered Malartin for 3 days and SP as a single dose on day 0. Only 174 of the subjects were successfully followed up on days 3, 7, and 14. The overall success rate of the drug combination was 92.53%. Parasite density decreased during the follow-up period in different age groups, sexes, and social classes. The prevalence of anaemia decreased from 22.99% at enrolment to 9.77% on day 14, and the difference was significant (P &lt; 0.05) on all days of followup. The drug combination did not give rise to any serious side effects