Potato (Solanum tuberosum) production in Africa is rapidly expanding and becoming increasingly important. As its geographical production range broadens, so does its potential to host new pests and diseases. Following the discovery that potato can be affected by Scutellonema bradys, further studies were undertaken to assess its potential pathogenicity on potato under screenhouse and field conditions, and on marketed tubers. Potato plants inoculated with S. bradys produced tubers with substantial cracking and evident tuber rot, compared with tubers from uninoculated plants. Symptoms of nematode infection on tubers included a scaly appearance, surface cracking as well as deeper tissue cracks, distortions, and darkened surface patches. In most cases these patches were related to sub-surface rot. Nematodes were recovered from the soil, roots and tubers of inoculated plants. Eight weeks after inoculation, the reproduction factor of the nematode was greatest (2AE0) at the lowest inoculation rate assessed (1000 nematodes per 2AE5-L pot) and least (0AE4) at the highest inoculation rate (5000 nematodes per pot). In the screenhouse, potato tuber weights were low and mostly unaffected by nematode inoculation rate, except at 5000 nematodes per pot. In the field, non-inoculated plants yielded over nine times more tubers than plants inoculated with 2000 S. bradys. Low densities of S. bradys were also recovered from 10 of 15 (67%) samples collected from market stalls, indicating field infection. This study confirms that potato can host and be damaged by S. bradys, raising its prospect as a likely significant biotic constraint to the crop.

It is abundantly clear that the population dynamics of plant parasitic or free-living nematodes have useful potentials as biomonitor for soil health and other forms of environmental contamination through agricultural activities, industrial pollution and oil spillage, and the analysis of nematode community structure could be used as complementary information obtained from conventional soil testing approaches.

Pot and field trials were conducted in 2012 and 2013 cropping seasons in Nigeria to determine the damage of Heterodera sacchari on the growth and yield of upland New Rice for Africa (NERICA) derived from hybridisation of Oryza sativa and O. glaberrima. NERICA rice (NR) cultivars selected were NR1, NR2, NR3, NR8 and NR14. In screenhouse experiments, rice seedlings were inoculated with 2500, 5000 and 10000 eggs and second-stage juveniles of H. sacchari, three weeks after sowing. In addition, two consecutive field experiments were carried out on a naturally infested field. Data on plant growth, yield, and final H. sacchari population densities were taken at the end of the experiments. Significant reductions of 34, 60 and 78% were observed in plant height, fresh root and total seed weights, respectively. Infected plants also produced chlorotic tillers and showed delayed panicle emergence. In field experiments, rice yield was reduced by approximately 50 and 85% in the first and second cropping seasons, respectively. Nematode population densities in soil and roots of rice plants increased significantly in infected plants compared to the controls. The results of this study indicate that H. sacchari is a serious pathogen of susceptible upland NR cultivars and may cause total crop failure when NR is continuously cultivated in cyst nematode infested fields.

Eleusine indica, Panicum maximum and Lablab purpureus were screened for their potential in remediating crude oil polluted soil in microplots. Five litres plastic pots were filled with 2 kg soil and treated with distilled water (which served as the control -0 ml) 40 ml, 80 ml and 120 ml representing 0%, 2%, 4% and 6% (v/w) of crude oil, respectively. The test plants were randomly planted in the treated soil; the experiment was a 3 x 4 factorial in a randomized complete design with four replicates. Soil samples were collected for physicochemical parameters at the beginning and at the end of the study. Results indicated that total hydrogen hydrocarbon (TPH) reduced significantly (p ≤ 0.05) in the crude oil polluted soil. The TPH of 94.1% obtained was from P. maximum treated with 4% v/w crude oil, followed by P. maximum (94%) treated with 6% v/w of crude oil. P. maximum treated with 2% v/w of crude oil had TPH of 82.5%. L. purpureus treated with 6^% v/w of crude oil reduced pollutant significantly with a TPH of 93.7% (6% v/w), 92.7% (4% v/w)) and 88.4% (2% v/w). In treated E. indica TPH was 87.7% (2% v/w), 91.4% (4% v/w), and (89.3% (6% v/w) in that order. The concentration of crude oil before and after remediation ranged from 456.10 -1712.20 mg/kg and 51.21 -183.62 mg/kg, respectively. Furthermore, there was increase in the pH of P. maximum by 35.8% at the contamination level of 6% v/w from 3.50 -5.45 pH pre and post remediation respectively when compared with the control. Soil cation exchange capacity reduced significantly in all tested plants with P. maximum being the least affected at all levels of crude oil pollution.There was no remediation of nitrates and phosphates by all test plants. However, phosphate in Eleusine indica treated with 6/% v/w of crude oil increased by 48% with the concentration of 6.50 mg/kg (pre remediation) to 12.50 mg/kg (post remediation), followed by Lablab purpureus 40.9% with concentration of 6.50 -9.60 mg/kg (pre remediation) to 9.60 mg/kg (post remediation) Evidently, the tested plants have remediation potentials of crude oil polluted soil.

Inflorescence dichotomous cultivars of false horn plantain (Musa spp.) is facing potential genetic erosion and extinction of its gene pool as a result of desertion, poor management practices, pests and diseases. Field trials were conducted at the University of Uyo Teaching and Research Farm during the 2017/2018 and 2018/2019 planting seasons to determine the effect of paring plantain suckers dipped in neem extracts and fertilizer sources on growth and yield related components of dichotomous plantain. The experiment was laid out in a randomized complete block design RCBD and replicated four times. The treatments consisted: pared sucker + 10% neem extract +10 t ha-1 poultry manure (PM); pared sucker + 10% neem extract + 20 t ha-1 PM; pared sucker + 10% neem extract + 400 kg ha-1 NPK 15-15-15 fertilizer; pared sucker + 0 t ha-1 PM and unpared sucker + 0 t ha-1 (which served as controls). Data collected on growth and yield related components were subjected to analysis of variance at 5% level of significance. Results indicated that pared suckers treated with neem extract and fertilizer sources had positive effect on growth and yield of inflorescence dichotomous plantain. However, unpared suckers + 0 t ha-1 were significantly (p>0.05) poor in growth and yield. The growth and yield parameters in the mother and first ratoon plants of pared suckers + 10% neem extract + 20 t ha-1 PM were significantly (p<0.05) superior than other treatment applications, notably, with taller pseudostem height which ranged from 306.50 to 309.50 cm, larger pseudostem girth ranged between 60.70 and 65.60 cm, number of suckers produced at harvest ranged from 9.50 to 10.00, fruit length ranged from 24.17 to 24.42 cm while the fruit diameter were between 17.83 and 18.17 cm respectively. In addition, the fruits in treated suckers increased significantly with yield ranging from 22.72 to 23.28 t ha-1 respectively. Consistently, pared plantain suckers dipped in 10% neem extract cum 20 t ha-1 PM in the field could effectively improve yield and encourage sustainability of inflorescence dichotomous plantain performance.