**6. Insect pest of cucumber**

Three insect pests are of high importance to cucumber production. They are cucumber beetle (striped and spotted), green peach and melon aphids. Cucumber beetle cause direct feeding damage and can vector bacterial wilt. Aphids on the other hand vector viruses.

#### **6.1 Striped and spotted cucumber beetles**

Striped cucumber beetles, Acalymma vittata (Fabricius), and spotted cucumber beetles, *Diabrotica undecimpunctata howardi* (Barber) share a similar life cycle, and inflict similar damage to host plants. Both species of cucumber beetles not only feed on the roots, stems, foliage and fruit of cucumbers they also vector diseases of cucumber [98]. Cucumber beetles vector bacterial wilt and can transmit another important disease, however, spotted cucumber beetles do not vector bacterial wilt disease but can spread squash mosaic virus and there are reports that they can increase the incidence of powdery mildew, black rot, and Fusarium wilt [99]. The feeding injury and disease transmission takes place from emergence until they form runners. Beetle cause growth retardation and destruction of young seedlings causing loss to the farmers.

#### *6.1.1 Management*

There is usually a peak in beetle activity each spring that lasts two to four weeks. This is the most important time to control beetles. Monitoring is as important as control which should be done as soon as seedlings emerge because early treatment is essential for beetle management in cucumber fields. Treatment should be carried out at the peak of beetle activity with foliar insecticides to protect cucumber plants from beetle feeding and transmission of bacterial wilt.

#### **6.2 Aphids (***Myzus persicae* **and** *Aphis gossypii***)**

A number of aphid species which include green peach aphid (*Myzus persicae*) and melon aphid (*Aphis gossypii*) feed on cucumber and cause similar damage. The aphids suck plant fluids from stems, leaves, and other tender plant parts using their slender mouthpart to pierce. Downward curling and crinkling of the leaves of infested plants is part of the first sign of aphid damage. The aphids are often found on lower leaves, soft-growing tips, flower buds, and in some cases flowers. The feeding activity of the aphids usually causes a variety of symptoms, which can

**191**

**Author details**

and Itunu Adeyemi Osijo

provided the original work is properly cited.

Olawale Arogundade\*, Titilayo Ajose, Joshua Olumide Matthew

malathion (0.05%) are used to control aphids.

National Horticultural Research Institute, Ibadan, Oyo State, Nigeria

© 2021 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium,

\*Address all correspondence to: arogundade\_olawale@yahoo.co.uk

*Current and Emerging Pests and Diseases of Cucumber (*Cucumis sativus *L.) in Africa*

include reduced plant growth and vigour, mottling, yellowing, browning, curling, or wilting of leaves. All these can result in low yields and sometimes death of

The Saliva that is injected into plant tissues by aphids can cause puckering and curling of leaves and such can protect them from natural enemies and help them evade substances applied for their control. Aphids feeding on flower buds and fruits can cause malformed flowers or fruits. Aphid is very prolific so populations can increase rapidly as each adult reproduces numerous nymphs in a very short period of time. It takes the green peach aphid just 10–12 days to complete one generation and can reproduce over 20 generations annually under mild climates [100]. Aphids generally are considered the most important vector for the transmission of viruses throughout the world with equal capability of both nymphs and adults [101].

The first step to management is early identification. The ability of aphids have to multiply rapidly must be taken into account while monitoring for this pest. Plants should be checked on a regular basis, at least twice a week with special attention to the undersurface of the leaves in most cases problems occur toward the end of the growing season. There are a number of cultural and biological options available depending on environmental factors and available resources. Yellow sticky traps would be helpful in detecting aphids 2–3 weeks prior to planting and can also help in management afterwards. The use of a detergent and vegetable oil solution before destroying old crops can avoid winged virus-infected aphids from getting to nearby crops to overwinter. Chemicals both organic such as potassium soap and petroleum oil or primicarb. Endosulfan, Dimethoate, Lannate, Fulfil, and Actara and inorganic like Cypermethrin (0.01%), acetamiprid (0.01%), bifenthrin (0.01%) and

*DOI: http://dx.doi.org/10.5772/intechopen.96692*

plant [100].

*6.2.1 Management*

#### *Current and Emerging Pests and Diseases of Cucumber (*Cucumis sativus *L.) in Africa DOI: http://dx.doi.org/10.5772/intechopen.96692*

include reduced plant growth and vigour, mottling, yellowing, browning, curling, or wilting of leaves. All these can result in low yields and sometimes death of plant [100].

The Saliva that is injected into plant tissues by aphids can cause puckering and curling of leaves and such can protect them from natural enemies and help them evade substances applied for their control. Aphids feeding on flower buds and fruits can cause malformed flowers or fruits. Aphid is very prolific so populations can increase rapidly as each adult reproduces numerous nymphs in a very short period of time. It takes the green peach aphid just 10–12 days to complete one generation and can reproduce over 20 generations annually under mild climates [100]. Aphids generally are considered the most important vector for the transmission of viruses throughout the world with equal capability of both nymphs and adults [101].
