The concept of sustainability has become central to all sectors all over the world, from agriculture to environment to business, engineering and industrialization. The principle of sustainability is the same all over these sectors. However, the understanding of the term may vary from sector to sector depending on how it may be applied to a specific sector. Sustainable agriculture is a term that continues to gain prominence in the agricultural sector but not without lots of misunderstanding, controversy and challenges. It is necessary that the sector has a common understanding of this term if it has to be applied by all and sundry. This is more so today due to the heightened importance of sustainable agriculture following its elevation to a key target in Sustainable Development Goal No. 2. This paper has been necessitated by the need to address the divergent perceptions of sustainable agriculture, which make it difficult to universally apply the concept in the agricultural sector and which could adversely affect the attainment of the goal's target. Sustainable agriculture has been wrongly linked to a return to either the low yields or poor farmers that characterized the 19 th century and the use of low value labour-intensive agricultural resources and production systems. It has also been viewed as an attack on conventional agriculture and intended for use by resource-poor farmers. With these perceptions, a common way forward towards sustainable agriculture is not possible. The paper highlights the varied but related definitions of sustainable agriculture and suggests that because of the "boundary object" nature of the definition, the principles of sustainable agriculture should provide a good guide to be followed in pursuit of the same. The paper suggests possible reasons why sustainable agriculture concept is not widely applied in Africa and proposes important actions to be undertaken to enhance wider application of this concept in agricultural systems.

Two NeemAzal products from Trifolio GmbH, Germany, and neem oil and neem seed cake powder of the Kenyan neem tree were tested for their efficacy against the storage pest P. truncatus in the laboratory at (a) low, (b) medium and (c) high rates, containing approximately 1.5, 3 and 6 mg azadirachtin A/kg maize, respectively. The maize samples were stored in 250 ml glass jars at 30°C and 70% relative humidity. After one month of storage, NeemAzal PC KG 01 (0.1% azadirachtin A) at all the tested rates and neem seed oil at high rates caused more than 80% mortality compared with 4% in the control. The two compounds also reduced weight loss to less than 20% of the loss in the control. Neem oil at high rates resulted in the highest mortality after 24 h. Most of the mortality caused by the NeemAzal PC KG 01 at all rates occurred within 7 days of treatment. Insect population increase was completely inhibited by rates of more than 7.5 ml/kg (approx. 22.5 mg azadirachtin A/kg maize) of neem oil and 3 mg azadirachtin A/kg maize of NeemAzal PC KG 01, while the lower dosage levels of neem oil also resulted in significantly fewer progeny compared with the untreated control. Neem oil caused larval mortality in their early developmental stages within the grains. These results are discussed in relation to the existing widely varied reports on the same subject.

Cassava is an important food security crop in Western and Coastal counties of Kenya. As a food security crop, it is continuously cultivated with minimal inputs. Its production is constrained by factors like declining soil fertility, poor agronomic practices, pests and diseases. Cassava brown streak disease (CBSD) is a viral infection attacking the cassava crop causing yield losses of up to 100%. The current study was intended to determine the effect of planting technologies on the prevalence of CBSD in two agro-ecological zones of Western Kenya: lower midland (LM1) and upper midland (UM1). Various spacing arrangements, four fertilizer regimes, legume intercrop and improved cassava cultivars were tested in a randomised complete block design (RCBD) with each site as a replicate. Data was collected on pathogen population and disease incidences and severity, and cassava and legumes yields. Results showed no effect of modified spacing and legume intercrop on CBSD incidence. However, incidences varied by cassava cultivar (9 to 59%) and fertilizer application (3 to 41%). Low CBSD incidences (3 to 16%) were observed over time in management strategies involving fertilizer NPK 17:17:17 suggesting that vigour enhancement may have contributed to low CBSD incidences. Low incidence of CBSD on improved cultivars indicates that CBSD can be mitigated through crop improvement technologies such as breeding for resistance to diseases. Intercropping cassava with beans and modification of spacing did not demonstrate an effect on CBSD incidence. However, 2 m× 0.5 m spacing arrangement can compensate for rising land pressure in Western Kenya and areas facing similar problem.

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Plant Stress detection is a vital farming activity for enhanced productivity of crops and food security. Convolution Neural Networks (CNN) focuses on the complex relationships on input and output layers of neural networks for prediction. This task further helps in detecting the behavior of crops in response to biotic and abiotic stressors in reducing food losses. The enhancement of crop productivity for food security depends on accurate stress detection. This paper proposes and investigates the application of deep neural network to the tomato pests and disease stress detection. The images captured over a period of six months are treated as historical dataset to train and detect the plant stresses. The network structure is implemented using Google’s machine learning Tensor-flow platform. A number of activation functions were tested to achieve a better accuracy. The Rectifier linear unit (ReLU) function was tested. The preliminary results show increased accuracy over other activation functions.