*1.4.1.3 Biological control*

Beneficial insects like predators, parasitoids, and pathogens are attracted to plants with moderate to heavy aphid infestations. These natural enemies may attack large numbers of aphids but as the reproductive potential of aphids is very high hence, the impact of the these natural enemies may not be enough to keep the aphids population below economic threshold levels. Lady bird beetles and their larvae *(Hippodamia convergens, Harmonia axyridis, Coleomegilla maculata)* [46], larvae of the syrphid fly [47], minute pirate bug *(Orius tristicolor* and *O. insidiosus)* and green lacewing larvae (*Chrysoperla carnea, Chrysopa spp*.) and brown lacewing larvae *(Hemerobius spp.)* and larvae of the aphid midge *(Aphidoletes aphidimyza*) [48] are common predators of aphid and help in natural control of this pest. Parasitoids comprises important place among natural enemies of aphid [49]. Some commonly found aphid parasitoids are *Aphidius matricariae, Aphidius colemani*, *Binodoxys angelicae and Lysiphlebus fabarum* [50]. Under humid conditions, Some fungi infect and provide biological control of aphid population, the most common entomopathogenic fungi are *B. bassiana, M. anisopliae, Verticillium lecanii* [51], and *B. bassiana* must be applied three times at an interval of 5–7 days for good control. Entomopathogenic fungus could be more effective than insecticides for controlling large populations of aphids if utilised properly.

### *1.4.1.4 Chemical control*

Potassium soap and petroleum oil or Actara are recommended for the management of this pest. Killing of aphid population should be done before destroying old crops to avoid winged virus-infected aphids from getting to nearby crops by using a detergent and vegetable oil solution. Acetamiprid (0.01%) or Cypermethrin (0.01%) or malathion (0.05%) can be used to control aphids.

#### **1.5 Whitefly (***Bemisia tabaci, B. argentifolii and Trialeurodes vaparariorus***)**

Cucurbits are attacked by several species of whiteflies. Of these, silverleaf whitefly *(Bemisia argentifolii),* tobacco whitefly *(Bemisia tabaci),* and greenhouse

**137**

of whiteflies.

*1.5.1.3 Biological control*

*Integrated Pest Management for Cucurbits in Cucumber (*Cucumis sativus *L.)*

whitefly *(Trialeurodes vaporariorum)* are the most devastating. Whiteflies are small in size about 1–1.5 mm long and the body and wings of adult are covered with fine whitish powdery wax. Adults and eggs are commonly found on younger leaves while nymphs are present on older leaves. A female lays around 300 eggs [52]; eggs are oval in shape and are laid by making a slit in the leaf. Initially the eggs are white, changing to brown colour, and are hatched within 8–10 days. The first instar is known as called crawler is the only mobile instar that moves to look for feeding sites, while the other instars are sessile and complete its life cycle on the same feeding site [53]. One generation of whitefly completes in about 3–4 weeks. The silverleaf whitefly gets injects a toxin into the plant that causes whitening of the under surface of newly emerging leaves. Severe damage may be occur on younger plants compared to older plants. Whitefly directly affects the cucurbits by its feeding and by acting as a vector of viruses. Cucurbit yellow stunting disorder virus, Cucurbit chlorotic yellow virus, beet pseudo yellow virus, and lettuce infectious yellows virus, are exclusively transmitted by whiteflies in both field and greenhouse-grown cucurbits [54]. Whiteflies also excrete honeydew which promotes the growth of sooty mould on leaves and economic

For early detection and monitoring the activity of whiteflies in the field, yellow sticky traps can be used. These traps are very important step for their management

Crop rotation, mulching, floating row covers, non-infested transplants, cover crops, and good field sanitation are some common cultural practises to prevent the build-up of whiteflies. Delayed planting or host-free periods may reduces severity of infestation as temperature and rainfall influence whitefly population dynamics [56, 57]. Soil ground covers such as living or synthetic mulches have been found to suppress whitefly infestation [52, 58]. UV-reflective plastic mulch provide good management of silverleaf whitefly by repelling the adults flies, which minimize their colonisation and nymph population on zucchini squash and pumpkin [59]. Field sanitations an important practice to control whiteflies infestation, whitefly-transmitted virus incidence, and insecticide resistance. Crop residues that shelter whiteflies should be destroyed immediately after final harvesting to reduce their population and sources of plant viruses [60]. Weeds should be eradicated regularly from the crop as they can support large populations

Natural enemies of whitefly such as *Encarsia formosa*, *E. luteola,* and *Eretmocerus* 

*Paecilomyces fumosoroseus* are very useful to suppress whiteflies in both field and greenhouse crops [62]. The important predators affecting whiteflies are true bugs (Miridae, Anthocoridae), beetles (Coccinellidae), lacewings (Chrysopidae, Coniopterygidae),

*californicus* have been found quite effective in the greenhouse conditions [61]. Entomopathogenic fungi based products namely, *V. lecanii, B. bassiana* and

distance

of whitefly. Traps should be placed just above the canopy at every 100 m<sup>2</sup>

of the crop as whiteflies are most attracted toward young foliage [55].

*DOI: http://dx.doi.org/10.5772/intechopen.97123*

plant parts.

*1.5.1 Management*

*1.5.1.1 Monitoring*

*1.5.1.2 Cultural methods*

*Integrated Pest Management for Cucurbits in Cucumber (*Cucumis sativus *L.) DOI: http://dx.doi.org/10.5772/intechopen.97123*

whitefly *(Trialeurodes vaporariorum)* are the most devastating. Whiteflies are small in size about 1–1.5 mm long and the body and wings of adult are covered with fine whitish powdery wax. Adults and eggs are commonly found on younger leaves while nymphs are present on older leaves. A female lays around 300 eggs [52]; eggs are oval in shape and are laid by making a slit in the leaf. Initially the eggs are white, changing to brown colour, and are hatched within 8–10 days. The first instar is known as called crawler is the only mobile instar that moves to look for feeding sites, while the other instars are sessile and complete its life cycle on the same feeding site [53]. One generation of whitefly completes in about 3–4 weeks. The silverleaf whitefly gets injects a toxin into the plant that causes whitening of the under surface of newly emerging leaves. Severe damage may be occur on younger plants compared to older plants. Whitefly directly affects the cucurbits by its feeding and by acting as a vector of viruses. Cucurbit yellow stunting disorder virus, Cucurbit chlorotic yellow virus, beet pseudo yellow virus, and lettuce infectious yellows virus, are exclusively transmitted by whiteflies in both field and greenhouse-grown cucurbits [54]. Whiteflies also excrete honeydew which promotes the growth of sooty mould on leaves and economic plant parts.

#### *1.5.1 Management*

#### *1.5.1.1 Monitoring*

For early detection and monitoring the activity of whiteflies in the field, yellow sticky traps can be used. These traps are very important step for their management of whitefly. Traps should be placed just above the canopy at every 100 m<sup>2</sup> distance of the crop as whiteflies are most attracted toward young foliage [55].

## *1.5.1.2 Cultural methods*

Crop rotation, mulching, floating row covers, non-infested transplants, cover crops, and good field sanitation are some common cultural practises to prevent the build-up of whiteflies. Delayed planting or host-free periods may reduces severity of infestation as temperature and rainfall influence whitefly population dynamics [56, 57]. Soil ground covers such as living or synthetic mulches have been found to suppress whitefly infestation [52, 58]. UV-reflective plastic mulch provide good management of silverleaf whitefly by repelling the adults flies, which minimize their colonisation and nymph population on zucchini squash and pumpkin [59]. Field sanitations an important practice to control whiteflies infestation, whitefly-transmitted virus incidence, and insecticide resistance. Crop residues that shelter whiteflies should be destroyed immediately after final harvesting to reduce their population and sources of plant viruses [60]. Weeds should be eradicated regularly from the crop as they can support large populations of whiteflies.

#### *1.5.1.3 Biological control*

Natural enemies of whitefly such as *Encarsia formosa*, *E. luteola,* and *Eretmocerus californicus* have been found quite effective in the greenhouse conditions [61]. Entomopathogenic fungi based products namely, *V. lecanii, B. bassiana* and *Paecilomyces fumosoroseus* are very useful to suppress whiteflies in both field and greenhouse crops [62]. The important predators affecting whiteflies are true bugs (Miridae, Anthocoridae), beetles (Coccinellidae), lacewings (Chrysopidae, Coniopterygidae),

spiders (Araneae) and mites (Phytoseiidae), [63]. *Conwentzia africana* (dusky lacewing) has been considered one of the most important predators of *B. tabaci* [64].

## *1.5.1.4 Botanicals*

Azadirachtin containing neem-based pesticide formulations like NeemAzal and Azatin have been found to control young nymphs and inhibit growth and development of older nymphs, and suppress egg laying by adult flies. Soap and certain oil sprays can be used in an organically certified crop. The efficacy of neem-based pesticides can be increased by adding 0.1%–0.5% soft soap in it.
