A Model for early detection of potato late blight disease: a case Study in Nakuru County

Thesis submitted in partial fulfillment of the requirements for the Degree of Master of Science in Information Technology (MSIT) at Strathmore UniversityThe agricultural sector has been a key backbone to Kenya’s economy. Agriculture has played a key role in the economy through agricultural farm produce exports and job creation hence improving and maintaining good farming practices is critical in ensuring agricultural yields. Potato (Solanum tuberosum L.) is a major food and cash crop for the country, widely grown by small-scale farmers in the Kenyan highlands. However, early detection of potato diseases such as potato late blight still remains a challenge for both farmers and agricultural extension officers.Consequently agricultural extension officers who play a critical role in training and creating awareness on sound agricultural practices are few and often lack sufficient knowledge and tools.Current techniques used for determining and detecting of crop diseases have heavily relied upon use human vision systems that try to examine physical and phenotypic characteristics such as leaf and stem color. This technique is indeed important for diagnosis of crop diseases, however the use of this technique is not efficient in supporting early detection of crop diseases. This study proposed use of sensors and back propagation algorithm for the prediction of potato late blight disease. Temperature and humidity sensor probes placed on the potato farms were instrumental in monitoring conditions for potato late blight disease. These parameters constituted abiotic factors that favor the development and growth of Phytophthora infestants. Back propagation neural network model was suitable for the prediction of potato late blight disease. In designing the potato late blight prediction model, historical weather data, potato variety tolerance on late blight disease was used to build an artificial neural network disease prediction model.Incoming data streams from the sensors was used to determine level and risk of blight. This study focused on a moderate susceptible cultivator of potato in developing the model. The algorithm was preferred due to its strengths in adaptive learning. The developed model achieved an accuracy of 93.89% while the precision obtained was 0.949. The recall ratio from the neural network was 0.968 and an F-measure of 0.964

The epidemiology and control of Leptosphaeria maculans cause of Crucifer Blackleg, in KwaZulu-Natal.

Thesis (Ph.D.)-University of Natal, Pietermaritzburg, 1996.The perfect stage of Leptosphaeria maculans is reported for the first time in South Africa. Viable pseudothecia and pycnidia were found on dead, weathered tissue, sometimes in close association, whereas only pycnidia were found on live tissue. Some seedlots of imported cabbage seed were found to be internally infected with L. maculans at low levels and Alternaria brassicicola at higher levels. Fungicides iprodione (dicarboximide), triforine and propiconazole (sterol-biosynthesis inhibitor) eliminated both pathogens from infected seed. In a field trial of eight cabbage and two cauliflower cultivars, incidence of stem infection by L. maculans ranged from 16-80%. Two seedlots of the cabbage cultivar Gloria Osena differed in blackleg stem susceptibility. No correlation was found between stem lesion incidence and foliar infection counts of each cultivar, or stem lesion incidence and each cultivar's average days-to-harvest. In a second trial, incidence of stem infection ranged from 50% (Rotan) to 95% (Dynasty) in cabbage, and 64.2 to 96.6% in cauliflower cultivars. All Brussels sprouts and broccoli cultivars tested were highly susceptible. The cultivars of turnip and tyfon tested were observed to be immune to blackleg, whereas the swedes, Japanese radish, chou moullier and red cabbage cultivars tested were highly susceptible. No correlation was found between stem length and incidence of stem infection. Different seedlots within several cabbage and cauliflower cultivars differed in their blackleg susceptibility. A third cultivar trial with 10 replicates of four seedlots of one cabbage cultivar confirmed that different seedlots of a single cultivar may vary significantly in their susceptibility to blackleg. Benomyl was applied to cabbage at the seedling stage only, or at the seedling stage followed by field applications every 14 d. Relative to an untreated control, multiple applications of benomyl resulted in a 33% reduction in stem infection, a ten-fold reduction in plants killed and a 50% reduction in the proportion of non-harvestable heads, relative to an untreated control. Seedling treatment resulted in a lower infection level, a lower mortality rate and a greater mean head mass than those of the untreated control. However, none of these differences were statistically significant. In a debris degradation trial, more than 90% of buried debris (cabbage stems infected by L. maculans) had decomposed after 2.5 yr, whereas 80% of surface debris had decomposed over the same period. The susceptibilities of seedbed transplants (SBT) and container-grown seedlings (CGS) were compared using different forms of L. maculans inoculum. "Dunk" inoculation of SBT into a pycnidiosporial suspension resulted in a stem infection level of 50% greater than an uninocu1ated control. Contamination of seedbeds resulted in an infection level of 46%. "Dunk" inoculation of CGS resulted in infection level of 22%. When CGS were grown in contaminated trays an infection level of 33.4% resulted. Interplot interference ill the form of inoculum dispersal over a 1 m border was low (1.8 and 2.7% for SBT and CGS, respectively) . In a further trial examining the relationship of inoculum level and blackleg, a strong interaction was found between inoculation technique and inoculum level. Inoculation of field plots with infected debris was a more efficient technique than dipping seedlings into a pycnidiospore suspension prior to transplanting. Twenty nine blackleg epidemics were surveyed over 11 yr. Seedbed transplants (SBT) had been used in 83% of cases. Two cases (7%) had involved direct drilled seedlings (DDS). However, excess seedlings had been transplanted, making DDS epidemiologically equivalent to SBT. Three cases (10%) had involved container-grown seedlings (CGS) grown on mono cropped cabbage lands. Disease occurred in two patterns: in crops grown from SBT and DDS, blackleg occurred down the lines. In all CGS cases, disease occurrence was randomly patterned. In all cases, diseased debris was found in seedbeds and production fields. Disease spread in the field was limited to the two plants on either side of the initially infected plant, 1.3 m or less, suggesting that infection had resulted from splash dispersed pycnidiospores. The disease cycle was mono- or oligo cyclic but not polycyclic. Over a period of 6 yr, cabbage fields of 26 farms were each examined once for cruciferous weeds infected with L. maculans. No viable blackleg lesions were discovered on cruciferous weeds, suggesting that weeds play no role in the local crucifer blackleg pathosystem. A theory is proposed that windows of disease susceptibility open and shut during the different phenological stages of a crucifer's life, and that the susceptibility of different plant organs vary with the phenological state of the plant. It is also postulated that blackleg is a "low sugar disease". Disease incidence was lower in well fertilized cabbage plants than minimally fertilized plants. Organoleptic tests of cabbage cultivars correlated superior flavour and texture in cabbage with a high susceptibility to blackleg. An integrated management strategy is proposed, based on seed treatment with fungicides, the use of container-grown seedlings rather than seedbed transplants, a 3 yr rotation of crucifer lands with non-cruciferous crops, implementation of either deep-ploughing or accelerated biodegradation to eliminate debris, the development of higher levels of horizontal resistance to L. maculans in cruciferous vegetables, application of field fungicides in high risk areas (benzimidazoles or triazoles, or combinations), and the minimization of stress and optimization of host nutrition

Genetic Glass Ceilings

As the world’s population rises to an expected ten billion in the next few generations, the challenges of feeding humanity and maintaining an ecological balance will dramatically increase. Today we rely on just four crops for 80 percent of all consumed calories: wheat, rice, corn, and soybeans. Indeed, reliance on these four crops may also mean we are one global plant disease outbreak away from major famine. In this revolutionary and controversial book, Jonathan Gressel argues that alternative plant crops lack the genetic diversity necessary for wider domestication and that even the Big Four have reached a “genetic glass ceiling”: no matter how much they are bred, there is simply not enough genetic diversity available to significantly improve their agricultural value. Gressel points the way through the glass ceiling by advocating transgenics—a technique where genes from one species are transferred to another. He maintains that with simple safeguards the technique is a safe solution to the genetic glass ceiling conundrum. Analyzing alternative crops—including palm oil, papaya, buckwheat, tef, and sorghum—Gressel demonstrates how gene manipulation could enhance their potential for widespread domestication and reduce our dependency on the Big Four. He also describes a number of ecological benefits that could be derived with the aid of transgenics. A compelling synthesis of ideas from agronomy, medicine, breeding, physiology, population genetics, molecular biology, and biotechnology, Genetic Glass Ceilings presents transgenics as an inevitable and desperately necessary approach to securing and diversifying the world's food supply

Effects of Complementary use of Organic and Inorganic fertilizers on the growth and yield of Cucumber (Cucumu sativus. L.) on an ultisol

A field study was conducted in 2008 and 2009 early cropping seasons to assess the response of cucumber (Cucumus sativus L.) to complementary use of organic and inorganic fertilizers in Uyo agro-ecology. The fertilizer treatments were: NPK (15:15:15) at 100 and 200 kgha-1, poultry manure (PM) at 5 and 10 tha-1 , and complementary application of 100 kgha-1 of NPK + 5 tha-1 of PM, 100 kgha-1 of NPK + 10 tha-1 of PM, 200 kgha1 of NPK +5 tha-1 of PM ,200 kgha-1 of NPK +10 tha-1 of PM and control (no fertilizer). Results showed significant differences (P<0.05) in all the growth and yield parameters considered in both cropping seasons. The combined application of 200 kgha-1 of NPK and 10 tha-1 of PM performed better than sole application of either organic or inorganic fertilizer, with fresh fruit yield of 14.63 and 14.92 tha-1 in 2008 and 2009, respectively and exceeded other treatments by 1 -76% and 1-73% in 2009 and 2010, respectively. This indicates strongly the synergistic benefits of using both organic and inorganic fertilizers even at lower rates