African Journal of Crop Science

African Journal of Crop Science ISSN 2375-1231 Vol. 8 (2), pp. 001-008, February, 2020. © International Scholars Journals

Full Length Research Paper

Life history of the potato psyllid Bactericera cockerelli (Homoptera: Psyllidae) in controlled environment agriculture in Arizona

Abdullah N. M. M

Department of Plant Protection, Faculty of Agriculture, Sana'a University, Sana'a, Yemen,. E-mail: [email protected].

Accepted 14 October, 2019

Abstract

The life history parameters were studied for a western isolate of Bactericera cockerelli (Sulc) from a southern Arizona commercial tomato greenhouse (AZ - 06) during 2006. Life history parameters were determined at 26 - 27°C and 60 - 70% humidity, with a 12:12 day/night cycle. The mean pre-mating period was 4.2 days, with a range of 3.8 – 5 days, and the mean pre-oviposition period was 6.9, with a range of 5.9 – 8.0 days. The mean incubation period for the egg stage was 6.7 days (range 5.7 - 8.2 days), with a nymphal period of 21.9 (19.1 - 23.8 days). The total developmental period was 25 to 33 days, with an average of 28. days. The survival of eggs, nymphal stage and total (all stages) survival was 62.7, 47.3 and 40.6%, respectively. The complete life cycle at 26 - 27°C required 34.7 days, ranging from 29.9 to 37 days. Female’s fecundity was 231.8 eggs per female, with a range of . The longevity for single females and males when reared separately from one another was 48.7 and 22.0 days. In contrast, when males and females were reared together on the same leaf they lived for the same number of days (41.5 days), irrespective of sex. It is not clear if the discrepancies noted here in life history traits are due to genetically inherited differences among different psyllid isolates, as they could as readily be modulated by environment and/or even their histories of host plant association. Also, an additional possibility by which differences in fitness observed herein, compared to psyllid isolates studied previously (for which no voucher specimens are available), might be due to infection by some prokaryotes like Wolbachia, which already reported in literature that might influenced host fitness, e.g. fecundity and longevity.

Key words: Bactericera, fecundity, longevity, life cycle, tomato pest.

African Journal of Crop Science ISSN 2375-1231 Vol. 8 (2), pp. 001-005, February, 2020. © International Scholars Journals

Full Length Research Paper

Response of some lowland growing sorghum (Sorghum bicolor L. Moench) accessions to salt stress during germination and seedling growth

Kinfemichael Geressu and Melkamu Gezaghegne

Department of Biology, Mekelle University (MU), Ethiopia, P. O. Box 231, Tel. +251-911-16-94-92, Fax: +251-344-409304

Accepted 15 November, 2019

Abstract

This research aimed to investigate the response of some lowland growing sorghum (Sorghum bicolor L. Moench) accessions to salt stress during germination and seedling growth. Twenty lowland sorghum (S. bicolor L. Moench.) accessions were tested during germination and seedling stage at 0, 2, 4, 8 and 16 dS/m salinity levels. Data analysis was carried out using jmp5 (version 5.0) statistical software. Final germination percentage (FGP), germination rate (GR), seedling shoot length (SSL) and seedling root length (SRL) were measured. The ANOVA for accessions found to be insignificant for most parameters recorded (p>0.05) but it was significant with respect to seedling root length (SRL) (p<0.0001). The ANOVA for treatments was significant with regard to all parameters measured (p<0.0001) . Germination rate and seedling root length were more salt affected than final germination percentage and seedling shoot length respectively. Accessions such as 235461 and 69239 were found salt tolerant during germination and seedling growth. However, accessions 223550, 69029, and 23403 were salt sensitive during germination but later became salt tolerant at seedling growth. Accession 223247 was found salt-sensitive during germination and seedling growth. The rest sorghum accessions were intermediate in their salt tolerance. The study affirmed the presence of broad intraspecific genetic variation among sorghum accessions for salt tolerance.

Key words: accessions, germination, NaCl, salinity, sorghum.

African Journal of Crop Science ISSN 2375-1231 Vol. 8 (1), pp. 001-007, January, 2020. © International Scholars Journals

Full Length Research Paper

Effect of rotation of cowpea (Vigna unguiculata) with fonio (Digitaria exilis) and millet (Pennisetum glaucum) on Macrophomina phaseolina densities and cowpea yield

Mbaye Ndiaye¹, Aad. J. Termorshuizen² and Ariena H. C. van Bruggen²

¹Centre Régional AGRYMET, Département de Formation et de Recherche, BP. 12625 Niamey, Niger.

²BLGG Company, Nieuwe Kanaal 7 f, 6709 PA Wageningen, The Netherlands (formerly: Biological Farming Systems Group, Wageningen).

³Biological Farming Systems Group, Wageningen University and Research Centre, Marijkeweg 22, 6709 PG Wageningen, the Netherlands.

Accepted 10 October, 2019

Abstract

Macrophomina phaseolina, the causal agent of charcoal rot, causes great damage to cowpea in the Sahel. One of the few options to manage the disease is by cropping nonhosts that may reduce the soil inoculum below a damage threshold level. To test this, fonio (Digitaria exilis) and millet (Pennisetum glaucum) were cropped continuously for 3 years in plots with a natural infestation of 24 - 53 microsclerotia g^-1 soil at the onset of the experiment. Next, a susceptible cowpea variety was grown to quantify disease incidence and severity on these soils. Fonio and millet both reduced microsclerotial densities in soils from the first year onwards. Reductions under fonio (81% after the 2^nd year; 86% after the 3^rd year) were significantly stronger than under millet (56 and 66% for the 2^nd and 3^rd year respectively). Fonio was not infected by M. phaseolina, while the root systems of millet had low densities of microsclerotia. Cowpea yielded significantly more hay and pods after 3 years of fonio than of millet. Cowpea yields and disease incidence (dead plants) could be explained well by pre-planting microsclerotial densities. We conclude that rotation of cowpea with a gramineous crop may lead to a relatively fast decline of inoculum density. In the case of a high inoculum density, fonio can be grown for three years to reduce M. phaseolina densities in soil.

Key words: Charcoal rot, fonio, millet cowpea, crop rotation, Sahel.

African Journal of Crop Science ISSN 2375-1231 Vol. 7 (11), pp. 001-007, November, 2019. © International Scholars Journals

Full Length Research Paper

Testing biological methods to treat rubber effluent

M. A. Iyagba¹, A. Adoki²* and. T. G. Sokari¹

¹Department of Biological Sciences, Rivers State Univ of Science and Technology Port Harcourt, Nigeria.

²Shell Petroleum Development Co. Ltd, P. O. Box 263, Old Aba Road, Port Harcourt, Nigeria.

Accepted 22 May, 2019

Abstract

A study was conducted with the aim of treating and disposing of the effluent of an indigenous rubber company rich in PO₄^3- and NH₄⁺ and also determine the effect of the effluent on soil fertility. The basic method used for the biological treatment was aerobic digestion with glucose and magnesium amendments. Most naturally occurring aerobic heterotrophic bacteria in the rubber effluent were found to be capable of utilizing petroleum hydrocarbons as carbon and energy sources. Prominent among these bacteria were the genera of Micrococcus, Bacillus, Staphylococcus, Aerobacter, Proteus, Corynebacterium, Streptococcus, Aeromonas and Pseudomonas. The possibility of using the effluent as soil supplement was established. Oxidative digestion following amendment with glucose yielded only 53 and 40% reduction in levels of NH₄⁺ and PO₄^3- respectively. Addition of glucose and magnessium ions resulted in 95% reduction for NH₄⁺ and 47% for PO₄^3-, respectively. Our results indicate that rubber effluent can be disposed of (i) by controlled spread to agricultural soils as an fertilizing agent or (ii) by aerobic digestion before release in natural flowing waters.

Key words: Heterotrophic bacteria, rubber effluent, amendment, oxidative digestion.

African Journal of Crop Science ISSN 2375-1231 Vol. 7 (11), pp. 001-007, November, 2019. © International Scholars Journals

Full Length Research Paper

Division of labour in nakati (Solanum aethiopicum) production in central Uganda

Charles K. Ssekabembe and Thomas L. Odong

Department of Crop Science, Makerere University, P. O. Box 7062, Kampala.

Accepted 22 May, 2019

Abstract

Nakati (Solanum aethiopicum) production is labour intensive. This paper reports on the division of labour in the production of this crop in central Uganda. There is significant division of labour between husbands and wives. Heavy duty land preparation is mostly done by husbands and hired male labour in order to do it fast when large acreages of Nakati are involved. Hired labour (35%) does most of the land preparation and weeding. Women do hand weeding better than men. Sowing is predominantly done by men (50%) who claim better experience than the females in broadcasting the crop. Pest control is mostly done by husbands and hired male labour (78%). Most women can not carry the knapsack sprayer and are often busy with household work. Fertilizer application is also mostly done by men (56%). Harvesting is mostly done by family labour (42%), and mostly by males who can carry the heavy Nakati bundles from the fields. Marketing is predominantly done by husbands (87%). Sometimes wives opt to have a separate plot of Nakati to cater for their unique needs. Generally, men do most of the work in Nakati production but training for Nakati improvement ought to target both men and women. Women should be organized into groups which can also be voluntarily joined by husbands, and these groups can be easily trained by extensions agents. It is preferable for women extensions agents to train the women farmers’ groups because women are likely to relate to fellow women in this regard. Since women are usually busy with household work training should coincide with the dry season when there is less work in the field. Farmer field schools could also benefit Nakati growers.

Key words: Nakati, Solanum aethiopicum, labour, production, central Uganda.