Cucumber (Cucumis sativus L.) belongs to the Cucurbitaceae family. It is a major vegetable crop worldwide and develops rapidly, with a shorter time from planting to harvest than most crops. It is a monoecious annual climber or creeper that has been cultivated for over 3,000 years and is still widely cultivated today. The fruit is soft, succulent with high water content, roughly cylindrical and elongated with tapered ends. The plant shades one another, being allowed to creep on the ground thereby having a direct contact with some soil inhabiting disease causing organisms. Its creeping nature, pre-disposes the plant to pest and disease infestation. However, the production of cucumber fruits in Nigeria is very low due to some constraints such as incidence of diseases which reduces fruit yield. Presently, they are produced mainly in the northern states of Nigeria. Studies were conducted on the production of cucumber in south eastern Nigeria, in order to supplement the high consumption rate in the region. Planting in April had the lowest disease incidence (3.48%) and severity on leaves (1.20) and fruits (1.06), followed by September with lower disease incidence (3.60%), disease severity on leaves (1.22) and fruits (1.17) while July had the highest disease incidence (6.27%) and disease severity on leaves(1.56) and fruits (1.74). The yields during the April and September plantings were significantly (p<0 .05="" 1.21="" 1.31="" 1.35="" 19.10="" 216.90="" 221.10="" 481.60="" 483.60="" 76="" a="" agro="" also="" and="" april="" be="" best="" both="" by="" condition="" cucumber="" derived="" disease="" diseases="" ecology.="" followed="" fortnightly.="" fortnightly="" four="" fruits.="" fruits="" fungicide="" gave="" had="" have="" having="" hectare.="" hectare="" higher="" highest="" holland="" incidence="" july="" leaves="" lines="" lowest="" months.="" not="" of="" on="" other="" p="" per="" planting="" plants="" poinsette="" proven="" received="" receiving="" regime="" regimes.="" regimes="" remains="" respectively="" response="" savannah="" september="" severity.="" severity="" showed="" significant="" span="" spray="" sprayed="" supermarketer="" than="" that="" the="" those="" three="" time="" to="" tonnes="" two="" variety="" weather="" weekly="" were="" while="" with="" withstand="" yield="">
Cucumber (Cucumis sativus L.) belongs to the Cucurbitaceae family. It is a major vegetable crop worldwide and develops rapidly, with a shorter time from planting to harvest than for most crops (Wehner and Guner, 2004). The crop is the fourth most important vegetable crop after tomato, cabbage and onion in Asia (Tatlioglu, 1993); the second most important vegetable crop after tomato in Western Europe (Phu, 1997) and is the fourth most cultivated vegetable in the world after tomatoes, brassicas and onions (Wehner, 2007). In tropical Africa, the crop has not been ranked because of limited use. Cucumber is grown widely in different parts of the world. It is an all year round out door vegetable in the tropics and an important greenhouse vegetable especially in Northern Europe and North America (Mingbao, 1991). Phu (1998) stated that cucumber could be cultivated in the field during the summer and winter in greenhouses using artificial heating. Jizhe (1993) opined that cucumber is a typical vegetable of warm temperate and cool tropical areas that can be cultivated at any time of the year. At present; cucumber is cultivated as a field crop in most areas of the world under frost free conditions. Nu (1998) stated that cucumber is a warm season crop which can be cultivated at any time but has little or no tolerance to frost and that growth and development are favoured by temperatures above 20OC. In Nigeria, cucumber can be cultivated at anytime of the year. During the rainy season, the crop is grown under rain fed conditions and during the dry season using irrigation facilities; as a result the crop can be seen in most vegetable markets in Nigeria throughout the year. Many varieties of cucumber exist with varying shapes, skin colour and carotene content (Simon, 1992) .The variation in the performance of cucumber varieties has been widely documented by many scholars (Manyvong, 1997; Ajisefinanni, 2004), which could be as a result of environmental factors or genetic composition. It is also known for its edible fruits because it is delicious, crispy, high in nutrients, low in calories and excellent source of fibre needed for a healthy digestive system. In addition to its palatability and fairly good calorific value, it is reported to be highly important to human for its medicinal value. It is very useful for natural Diuretic and thus can serve as active drug for secreting and promoting the flow of urine. Cucumber is a dependable laxative food for those who suffer constipation. The juice of cucumber is a valuable medicinal food in the treatment of hyperacidity gastric and duodenal ulcers (Ernestina, 2001).
In Nigeria, Cucumber production and utilization have not been a viable option to farmers despite the numerous benefits and economic importance of this crop. This might be in part due to the declining soil fertility in conjunction with disease infestation, which prevents optimum yield and the short shelf life of cucumber fruits which leads to early deterioration.
Cucumbers are susceptible to viral, fungal and bacterial diseases. They are mostly affected by fungal diseases and this causes significant losses to cucumber crops and currently requires a high chemical use for their control. Among the fungal diseases is the phytophtora blight disease caused by Phytophtora capsici (Babadoost , 2005), which is prevalent in the south eastern Nigerian. It can develop on cucurbit plants at any stage of development; the pathogen can infect seedlings, vine, leaves and fruits. The infection usually appears first in low area of the fields where soil remains wet longer. It causes pre- and post- emergence damping-off in cucumber under wet and warm (20-30 °c) soil condition. Soil-borne diseases have led some growers to rely upon pesticides treatments. Besides the high annual cost of these treatments, poor application practices and easy re-introduction of pathogens due to poor hygiene and sanitation have resulted in frequent disease outbreaks. Furthermore, they are highly toxic chemicals that pose a significant risk to farm workers and neighbours.
This problem is exacerbated by the fact that there are no chemicals registered for most soil-borne pathogens in cucumbers. Similar problems exist for some foliar diseases (e.g. Botrytis blights and rots). There has been a rapid development and availability of biological control products worldwide, yet many of these products have not been objectively evaluated for efficacy. Similarly, many products have not been validated as part of integrated crop management systems for Nigerian conditions