cotton is at risk to a variety of terrible insect pests. Here, we share a guide to symptoms, identification and management of the significant threats

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Cotton bollworm

Larvae of the noodle bollworm moth Helicoverpa armigera cause severe damage to cotton plants reducing returns in numerous of the significant growing regions, including the USA, Mexico, Brazil, India and China. The adult female moth lays between 1,000-1,500, ribbed, spherical eggs in one cycle through the larvae emerging around three days later. The larvae strike the plant causing damages to the blooms that may open prematurely and also stay fruitless while seedcases (bolls) may autumn off or develop reduced quantities of noodle lint of inferior quality.

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Under optimum temperature conditions the cotton bollworm moth lifecycle is simply 35-40 days, an interpretation it is capable of developing three to four generations every crop.

Identification: The adult moth is about 35-40mm throughout with yellow/orange fore-wings, the bear a single dark spot and also paler second wings through a distal stripe. Eggs of about 0.6mm room visible close to flowers, bolls and on leaves. The emerging larvae are identifiable through dark, environment-friendly stripes.

Management control: Pheromone and light traps attract the moth enabling early detection and population estimates because that chemical control. Organic control contains the Trichogramma pretiosum fungus which strikes eggs.

Cotton boll weevil

Anthonomus grandis is a significant pest the cotton and also highly-mobile, travelling distances of end 70km in solid wind currents. The bug infests crops in North, south and main America whereby it strikes the occurring bolls, damaging the noodle lint inside. The condition has price growers in the USA hundreds of millions of dollars in yield losses and also control.

Identification: The adult weevil is grey/brown and about 5mm long, through a 3mm-long protrusion from the head, when the larvae are white grubs through brown mouthparts. Egg laying damage appears as puncture marks at the next of flower sprout which are covered by a secretion the hardens to form a hard blister.

Management control: chop rotation and also any other determinants that get plants growing quickly - good seed beds, at an early stage planting in great conditions, and treated seeds - will assist the plant reach a an ext mature and also robust stage by the time the weevil is active.

Cotton aphid

Aphis gossypii is discovered wherever the crop is grown throughout the world. In most regions the bug uses secondary host plants throughout its lifecycle. Sex-related reproduction in the autumn, yields plenty of eggs which overwinter come hatch as soon as spring temperatures rise over 10c. Beforehand signs of an infestation room yellowing leaves but as aphid number grow, the symptoms swiftly worsen, and also foliage starts to pucker and also curl. Without any kind of control the insect will eventually colonise the totality plant, depositing honeydew which climate attracts a black, sooty mould. Where this is the case, plant expansion will it is in stunted and also in the most extreme infestations, may also die.

Identification: The winged woman is tiny (less 보다 2mm) and ranges in color from the yellow legs, pale-green abdomen and also black head and also thorax. Wingless females are assorted shades of green with yellow legs and also antennae. Likewise, nymphs show shade variations indigenous green, tan and grey through a dark head, thorax and also wing pads. Eggs room yellow initially but quickly turn gloss black. Females can reproduce asexually (parthogenesis) with up come 50 generations a year.

Management control: Clearing second host plants, where feasible will reduce the aphids’ habitats because that egg laying and overwintering. This contains destroying volunteer cotton and plant trash. Monitoring for population thresholds should start at seedling emergence and also is recommended at weekly intervals in some cultivation regions. Counting the variety of aphids ~ above leaves have the right to then be compared and also converted come likely damages scores using typical data tables developed by part authorities. Organic controls encompass various parasitic species of beetles and also their larvae, particular wasps and also lacewing.

Spider mites

Spider mites which infest cotton include varieties such as Tetranychus urticae, T turkestani and T pacificus. These are uncovered in many cotton cultivation regions consisting of South America, South east Asia and Africa with variations in visibility or dominance of each of the three species. Mites have the right to spread across long distances and readily cross boundaries on imported plants, on clothing or in strong wind currents.

Identification: Mites are an ext closely-related to spiders 보다 they room to insects and have eight legs, are simply 0.5mm long and also can be eco-friendly or red depending on the species.Species might feed ~ above the upper or reduced leaf surfaces and the strongness of the damages can reason defoliation.

Management control: Weekly sampling should begin at seedling emergence and the frequency need to be boosted in hotter, drier weather. The mite has many predators which have the right to be presented including: thrips, certain ladybird types, damsel bugs, brown lacewing adults, and also tangleweb spiders. Spider mites deserve to survive on nearly any broad-leaved weed for this reason clearance that preferred secondary hosts such as turnip weed, deadnettle, and sowthistle, will reduce carry-over to the following cotton crop.

Mirids

Both green Creontiades dilutus and also Brown Creontiades pacificus space flying insects uncovered in Australia and also Eastern Asia where they damage cotton plants by introducing toxins throughout feeding. The adult and also nymph stages relax chemicals as soon as their mouthparts pierce tree tissues. This destroys cells and also can cause branching in the noodle shrub when farming points space killed. Bolls, buds and flowers may additionally be damaged resulting in significant yield and quality losses. Mirids lay egg by inserting every one into the tree tissue with an oval lid left protruding above the leaf petiole surface. The full lifecycle, indigenous laying come adult, takes about 21 days and the adult may then live because that a further four weeks.

Identification: The winged adult green Mirid is pale green, about 7mm long with red markings, if the pear-shaped nymph has red/brown tips on that antennae. Brown Mirids differ due to the fact that they have actually a brown head and thorax and are slightly bigger at about 8mm long. At the nymph stage their antennae have actually red/brown and also white stripes.

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Management control: Sampling to create infestation levels need to be carried out on a weekly basis at first with boost to twice-weekly at top fruit production when the chop is more vulnerable. Lucerne may be provided as a trap crop to draw the mirid native the cotton chop while removing plant trash and weeds such as wild turnip and thistles, will certainly limit the possibility for overwintering.