The lifecycle of helicoverpa armigera and its impact on the cotton industry in Australia

Hausarbeit , 2023 , 13 Seiten , Note: A

Biologie - Botanik

The life cycle of Helicoverpa armigera, commonly known as the cotton bollworm, is a significant concern for the cotton industry in Australia. This paper explores the various stages of the bollworm's life cycle, including egg deposition, larval feeding, pupation, and adult emergence. The impacts of Helicoverpa armigera on the cotton industry are examined, highlighting the substantial economic losses incurred due to yield reduction and increased pesticide use. The paper further discusses effective management strategies, such as integrated pest management techniques, genetically modified cotton varieties, and targeted pesticide application. Implementing a comprehensive approach to control Helicoverpa armigera can help mitigate its detrimental effects on the cotton industry in Australia.

Abstract

"The life cycle of Helicoverpa armigera, commonly known as the cotton bollworm, is a significant concern for the cotton industry in Australia. This abstract explores the various stages of the bollworm's life cycle, including egg deposition, larval feeding, pupation, and adult emergence. The impacts of Helicoverpa armigera on the cotton industry are examined, highlighting the substantial economic losses incurred due to yield reduction and increased pesticide use. The abstract further discusses effective management strategies, such as integrated pest management techniques, genetically modified cotton varieties, and targeted pesticide application. Implementing a comprehensive approach to control Helicoverpa armigera can help mitigate its detrimental effects on the cotton industry in Australia."

1:1 Introduction

Helicoverpa armigera (cotton bollworm) is a widely known agricultural insect pest that can cause severe damage. The pest causes damage to various types of crops in zones of Australia and it is dominant in plants like cotton, tomatoes, chickpeas, maize, sorghum as well as some vegetables. (Mahmood et al, 2021) The life cycle of the cotton bollworms is highly dependent on temperature and therefore to manage its population one needs to have accurate information on such things as the temperature in the area of interest which is quite difficult information to gather. The female cotton bollworm lays eggs hundreds of them on several parts of a plant the eggs can hatch into larvae within three days if under favorable conditions, within a whole month the entire process will be complete. The Helicoverpa armigera is commonly referred to as the cotton bollworm since it mainly chooses cotton as the host plant. It mainly attacks the blooms and so they open prematurely making them fruitless, the bolls are exposed to damage and may fall off, fail to produce or either produce low-quality lint. Therefore, the cotton bollworm is a threat to the agriculture sector since it causes serious damage to the plants. The attack of Helicoverpa armigera on plants poses a lot of negativity to the agricultural industry and especially to the farmers who rely on cotton for instance. Low-quality cotton or no cotton produced at all is one major challenge posed (Mahmood et al, 2021). Millions of growers in Australia get their livelihood from cotton production and also crop production. The sector faces challenges since insects become resistant to insecticides, therefore, causing great losses. In this literature, review the information on Helicoverpa armigera given mainly focuses on the effects on the cotton industry and especially in Australia and its management. The review narrows to Helicoverpa armigera and what economic importance it poses to the Australian sector of agriculture. The review is vast since the literature on its management, ecology, and biology is important. The research also focuses on the use of host plant resistance, chemical, biological, and control.

2:1 The Life Cycle of cotton bollworm

The cotton bollworm is a serious pest in the southern sides and although damage has been limited in areas where infestations have been on the rise and it causes serious troubles to growers (Mahmood et al, 2021). The main thing that farmers or growers should focus on is the fruiting and boll development stages. An adult is usually a medium-sized cream-colored moth and can be seen mainly during the day in periods of heavy infestations (Klassen & Vreysen, 2021).

2:2 Eggs

The moths lay eggs on leaves and sometimes in squares within the canopy. The eggs are the size of a pinhead and are white to cream-colored which hatch within three days during warm weather.

2:3 Larva

The young larvae can be found when they are four days old when they are about a quarter an inch long brownish in color and with scattered hairs. When it is one and a half inches this is now a full-grown larva and has a light-colored head capsule. (Carde &Resh, 2021) The predominant color will mainly be between pink or green to various shades of dark brown. Larvae begin feeding on leaf tissue and move down the plant damaging the larger squares and bolls.

3:1 Ecology

The Helicoverpa armigera is a polyphagous pest meaning can eat a variety of crops. Where polyphagy usually has a crucial role in pest population persistence and hence might simultaneously develop several hosts within one region. This means that the population might also develop continuously during suitable periods by the use of several cultivated and uncultivated hosts in the season. Finally, it also means that the population can also persist at low density in unsuitable areas since the females have a high probability to locate a host easily.

4:1 Mobility

The Helicoverpa armigera is also able to successfully survive since it can move long distances after the polyphagy. The Helicoverpa armigera usually has two strategies and can cope with the seasonability of their environment, longitudinal rearrangement by relocation and diapause through periods of cold or drought times (Downes et al, 2017). The local movements within crops and other wild hosts are important in the dynamics of the seasons in the area. This is mainly experienced in the cropping systems where feeding and oviposition are available continuously.

5:1 Fecundity

The pest status of Helicoverpa armigera is its high fecundity and this enhances it with shorter generation time if offers to population outbreaks which have over 3000 eggs from a single female. The fecundity of Helicoverpa armigera is mainly influenced by temperature, humidity as well as the nutrition of the larvae and adults. The fecundity is obtained or achieved by different workers who reflect differences in the way adults are maintained in the lab. Laboratory estimates are however not so clear and there are no estimates realized in fecundity. (Noor-ul-Ane & Zalucki, 2018)

6:1 Control Measures

6:2 The host plant Resistance

To manage the Helicoverpa armigera, there are new developments of crop cultivars that are resistant to feeding damage and have great prospects in the management of his pest. Many crops tend to display characters that can be overly exploited by the breeders to reduce their attractiveness to the ovipositing adults or the appropriateness of larvae to feed. The value of host plant resistance usually depends on the type of resistance, the behavior of the pest, and the crop diversity system (Mahmood et al, 2021). The plant breeder at some point redresses the balance to exploit natural defense mechanisms existing in nature where such factors depend on temporary avoidance, chemical, and physical defenses.

6:3 Genetically modified crops

Modern Biotechnology DNA has the potential to benefit the Australian plant protection industry and the current techniques give the great potential of moving a cloned gene into any other organism offering great precision and speed to achieve results. Transgenic crops or genetically engineered crops have genes from unrelated sources, plants, or bacteria. This provides artificial techniques to move across boundaries. Two approaches have been used to make sure that there is a great contribution to the production of inherent resistance (Downes et al, 2017). Genetic engineering opens up a source of germplasm variability from which one can make a selection of Helicoverpa armigera control genes to the introduction of advanced crop varieties. transgenic plants have got protection from independent weather conditions, and efficient and effective control of bollworms, and pod-borers that tend to be difficult to reach during spray control at all stages of the development of insects.

7:1 The effects of Helicoverpa armigera larval stage on the host.

7:1:1Biological control

The cotton bollworm causes significant damage to crops and so there are insecticides that have been developed to fight this pest. The insecticides are made from biocontrol agents which is a parasite that is used to suppress e the pest population on the crops mainly cotton and chickpeas or any other crops that are affected by cotton bollworm. The commonly used parasite is the completis chloridae, Uchida. Change in the density of the parasitoid is the numerical response and this brings changes to host density. The impact of a parasitoid on its host population depends upon factors such as the ability to increase in number and find the hoists for the parasite. The rate of parasitization, which depends on the host number, is a crucial condition for both stability of the parasitoid host population and the success of biological control (Allahyari et al, 2020). The female parasitoid usually gets near the host and is attracted to it due to the odor of the host. When it gets to the region where the host is located female parasitoid finds the exact spot by use of the antennae and it is here it gives in to the final stimulus of oviposition. This causes an increase in parasitoid density and the number of emerging offspring increases with up to four parasitoids then shows a pattern of stability.

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• Note: A
• Autor: Rhoda Kariuki (Autor:in)
• Erscheinungsjahr: 2023
• Seiten: 13
• Katalognummer: V1365664
• ISBN (PDF): 9783346895158
• ISBN (Buch): 9783346895165
• Sprache: Englisch
• Schlagworte: cotton bollworm, helicoverpa amigera, pest management, lifecycle