Avocado is the leading horticultural export in Kenya. In 2003, Kenya exported about 19,000 t, compared to 23 t in 1970. Most of the fruit is exported to the European markets. There are several constraints limiting production of avocado in Kenya, including limited superior varieties or planting material, poor infrastructure, poor market information, and poor tree crop management. Although several diseases infect avocado, the most important are fruit rot pathogens, such as anthracnose, cercospora, and scab. However, diseases and pests have not been important to avocado production in Kenya. Recently (2004), the constraint limiting avocado production in Kenya is anthracnose, caused by Colletotrichum gloeospoirioides. Little is known in Kenya on the impact of this disease on production and income realized by small-(<1 acre) or large-scale growers. The objectives of this research were to quantify losses attributed to anthracnose in Kenya, determine the current disease control measures, and recommend good agricultural practice in conformance with EUREP-GAP. A survey was conducted in the avocado growing areas to identify and document constraints limiting avocado production in 2004. The highest losses were reported from central Kenya, where exporters reported up to 100% losses. Because all avocado varieties growing in Kenya are susceptible to anthracnose, it is recommended that good management, i.e., control of pests and diseases and good postharvest handling of fruit to minimize injury used as an entry point by anthracnose, should be enforced.
Lusike A. Wasilwa, Joseph K. Njuguna, Violet Kirigua, Charles N. Waturu, Richelle A. Stafne, Lusike A. Wasilwa and Teddy E. Morelock
Lusike Wasilwa*, Viincent M. Kega and Richelle A. Stafne
Citrus is one of the most important fruits in Kenya because of it's nutritional value. It is ranked as the highest source of income from tree crops in Kwale district of the coastal region. The average farmer has 0.25 to 4 acres of citrus and earns between 1 to 2 U.S. cents per fruit based on quality. Citrus gummosis (P. citrophthora and P. nicotianae) is of economic importance on citrus in Kenya. P. citrophthora prefers cooler conditions in the highlands and P. nicotianae favours the warm conditions of coastal areas. Several IPM options are being used to control this disease in Kenya. Research to select suitable rootstocks, determine the period when disease development is greatest and the distribution of infected trees in Kwale districts is currently being conducted. Gummosis has also been reported to occur in farmers fields around Marigat (Perkerra) and surrounding areas however the data is scanty and a detailed survey is underway. Gummosis disease incidence in Marigat was first reported in 1989/1990. Since then symptomatic trees have been treated with fungicides e.g. Ridomil. A citrus mother block consisting of 241 trees, established at Perkerra in 1984 now only supports 112 trees or 47% of the original trees. From the 112 trees, only 21 trees are classified as healthy trees. More extensive research needs to be conducted to show the impact of this disease on the small scale farmer and develop better methods of control.
Lusike A. Wasilwa, Grace W. Watani, N. Ondabu, A. Nyaga, B. Kagiri and S. Kiiru
Although macadamia was introduced to Kenya in 1946, it was not until the 1960s that commercial cutlivation commenced in the central, eastern, and western highlands. In the 1970s, 300 macadamia trees in the Central and Eastern highlands were selected based on nut yield and tree characteristics. In 1981, a subset of 25 of the most outstanding macadamia clones were planted (1979–1987) and evaluated at the National Horticulture Research Centre in Thika. Trial orchards, consisting seven to 15 clones (EMB-1, EMB-2, EMB-H, KMB-1, KMB-3, KMB-4, KRG-1, KRG-3, KRG-4, KRG-15, MRG-1, MRG-20, MRG-24, MRU-25, and TTW-2), were established in 1982, 1986, and 1989. The trials were set up as RCBD with five blocks and three to eight plants of each clone per block. Results from trial orchards show that macadamia hybrids (a natural hybrid between M. integrifolia and M. tetraphylla) EMB-H, KMB-3, and KMB-4 perform well at the higher elevations (>1700 m). The most outstanding clones of M. integrifolia with wide adaptability (1400 to 1750 m) were EMB-1, KRG-15, and MRG-20. Three distinct nut-bearing patterns [single peak (most varieties), bimodal peak, and ever-bearing] were observed. Nut clusters contain an average of 10 nuts (M. integrifolia) or 25 nuts (macadamia hybrid). Ten-year-old trees yield between 30 to 60 kg of nuts a year with kernel recovery of 28% to 41%.