Cotton Pest Management (original) (raw)
Related papers
Natural Mortality of Helicoverpa armigera (Hübner) Eggs in the Cotton Ecosystem
Journal of Agricultural Science and Technology
Field studies were conducted during the cotton crop seasons in 2003 and 2004 at CCS Haryana Agricultural University, Hisar, to identify mortality factors in the egg stage of Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) in the insecticide-free cotton fields to gain an insight into the role of these factors in causing egg specific mortality. Eggs were collected from cotton fields on different dates during September-November and brought to the laboratory for determining egg viability and level of parasitism. Similarly, plant parts bearing eggs in the field were tagged on different dates and observed daily to assess egg loss. The correlation of egg loss with various abiotic factors was determined. The mean viability of field collected eggs was 75% and 89% during 2003 and 2004, respectively (pooled mean egg viability of 82%). It was 51.34-66.55 (Mean: 59.72) % in the case of eggs deposited in the field by the laboratory-reared females. Eggs were parasitized by Trichogramma chilonis Ishii during September-October and mean parasitization was 25 and only 1-2% during 2003 and 2004, respectively. There was a positive correlation of % egg loss with wind velocity and rainfall as evident for multiple correlation coefficient values, i.e. 0.92 and 0.60 for 2003 and 2004, respectively. A partial ecological life table constructed for egg stage indicated that 23-44% mortality occurs at this stage. Important factors responsible for egg mortality/loss were identified as T. chilonis, inviability, rain, wind and unexplained mortality.
New Aspects of Biological Control of Helicoverpa armigera in Organic Cotton Production
One new approach in biological control of Helicoverpa armigera in organic cotton farms is the combined use of natural enemies (parasitoids and predators). The combination between p arasitism of Trichogramma species and predation of Chrysoperla carnea on Helicoverpa armigera was investigated in the laboratory and greenhouse. In the laboratory, the effect of preying time of Chrysoperla combined with Trichogramma on predation of H. armigera eggs for 1, 12 and 24 hours was studied. Moreover, e ffects of Chrysoperla predation on parasitized eggs by Trichogramma species after 2-3, 5-6 and 7-8 days were investigated. In the greenhouse, combined releases of Trichogramma and Chrysoperla were studied to control Helicoverpa on 4 cotton cultivars. Preying time of Chrysoperla both affected predation and parasitism rates. Predation rates increased with increasing preying time of Chrysoperla. Predation rates of Chrysoperla on parasitized Helicoverpa or Sitotroga eggs decreased with aging of parasitized eggs. The proportion of H. armigera eggs parasitized when both natural enemies were present differed significantly between Trichogramma species, being higher in T. pretiosum compared to T. minutum. On the other hand, the proportion of H. armigera eggs preyed in greenhouse cages was higher in T. minutum compared to T. pretiosum. Combining Trichogramma species and C. carnea for controlling H. armigera eggs resulted in higher mortality rates than Trichogramma alone. Predation and parasitism rates were affected by different cotton cultivars; they were higher on Giza 89 than on Giza 86, and they were also higher on a Bacillus thuringiensis cultivar (BT) than on non-Bacillus thuringiensis cultivar (non-BT). In most of the experiments Chrysoperla did not prey on parasitized eggs
Journal of Asia-pacific Entomology, 2007
Morphometric characterization of twelve geographic populations of cotton bollworm, Helicoverpa armigera occurring in south Indian cotton ecosystems was done at larval, pupal and adult stages over three cropping seasons. Traits such as length and weight of larvae, pupa and length and width of the wing, length of fore-, mid- and hind femur, male reproductive organ-length of genital capsule, valves, and ejaculatory duct, female reproductive organ-length of appendix bursae and ductus bursae at adult stage were measured across three years. Populations significantly differed for most of the traits studied. It was evident that populations from northern parts recorded higher phenotypic attributes compared to those from southern parts of south Indian cotton ecosystem. Besides larval, pupal and adult external phenotypic traits, attributes of male reproductive organ viz., length of genital capsule, valves, and ejaculatory duct and female reproductive organ viz., length of appendix bursae and ductus bursae differed significantly among populations. Information on population structure and differences based on morphometry would be useful in better understanding of population dynamics and management of this pest in cotton and other crops in south India.
Within-plant distribution of the immatures of Heliothis zea (Boddie) on cotton
1980
Within-plant distribution of four predators found in California cotton fields is described. Adult stages of all predators were found in greatest frequency in the terminal portions of the plant, and, within that region, adults tended to be more common on fruiting parts than the same species of larvae. In general, the smaller predators, Geocoris and Orius, were found higher on the plant than the larger predators Cbrysopa (larvae) and Nabis. Their respective areas of activity corresponded to the location of suitably sized (stages) prey. Those predators closest to the plant terminal were more effectively sampled with the standard University of California sweepnet. Within-plant Distribution of the Immatures of Heliothis zea (Boddie) on Cotton (Wilson, Gutierrez, and Leigh) A detailed study of the within-plant distribution of cotton bollworm (He/iothis zea (Boddie)), its eggs and larvae, was conducted in the field, and sampling schemes for them were developed. The average location of bollworm eggs was approximately one-third of the distance in nodes from the terminal, while older larvae were found lower on the plant than younger larvae. The sampling scheme for bollworm eggs relies on the finding that the mainstem leaves are the preferred oviposition site. Field observations indicate that early first instar larvae can be detected in squares by the presence of frass and the flaring of the bracts, These criteria are used in a suggested sampling scheme for first-through-third instar larvae. Fruit Predation Submodel: Heliothis Larvae Feeding Upon Cotton Fruiting Structures (Wilson and Gutierrez) Field and laboratory data on the numbers and age distribution of two varieties of cotton fruits, the association of various-age bollworm larvae (He/iothis zea (Boddie)) and various age fruit, as well as the attack rates of the larvae on the fruits were used to develop a submodel describing predation of bollworm larvae on cotton fruits. The submodel will be used in the coupling of bollworm-and cotton-plant population models. This model is an important step in the development of dynamic economic threshold levels for bollworm in cotton.
Manjunath, T.M., Ravi, K.C. and Mohan, K.S., 2004. Role of Alternative Host Crops of Helicoverpa armigera as Natural Refugia for Insect Resistance Management in Bt-Cotton in India. ‘All India Workshop on Insect Resistance Management (IRM) Strategies for Bt Cotton in India,” University of Agricultural Sciences, Dharwad, 29 -30 March 04, pp.4. Helicoverpa armigera, the most dominant pest of cotton in India, also infests several other economically important crops like pigeonpea, chickpea, sunflower, corn, chili, tomato and okra. Such crops are cultivated around the same time as cotton in several parts of central and south India and occupy substantial area. All these host crops supported large populations of H. armigera, especially pigeonpea and chickpea where the populations were significantly greater than on cotton. Mating studies conducted in the laboratory showed that moths from different host crops could interbreed and produce viable progeny. In view of this, it appears that growing non-Bt cotton as structured refuge need not be mandatory as these alternative crops can serve the same purpose by way of 'natural refuge' and contribute to insect resistance management strategy. This is further complimented by the fact that presently Bt-cotton occupied hardly about 6% of the total cotton area and the huge remaining cotton can also act as refuge.
Action Threshold Levels of Helicoverpa Armigera (HBN.) on Cotton at Different Stages of Plant Growth
International Journal of Research -GRANTHAALAYAH, 2018
The African bollworm, Helicoverpa armigera (Hbn.) (Lepidoptera: Noctuidae), is the most important cotton pest in all the cotton growing areas of the Sudan and most of the protection measures are directed for its management. The previous action threshold level for chemical control interference was increased in 1993 from 10 larvae and/or eggs /100 plants to 30 eggs or 10 larvae/100 plants and no spray to be conducted before flowering advances. This level was being subject to revision since 1999. Studies conducted at the Gezira Research Farm during 2001/2002, 2002/2003, 2003/2004, 2004/2005 and 2012/2013 were carried out on this regard at growth stages of cotton plants, i.e. Pre-flowering, flowering and bolls formation stages and the consequence on yield. Barac. (67) B cultivar, Gossypium hirsutum, was used. The action threshold levels were 10, 15, 20 eggs and/or larvae/100 plants and 30 eggs or 10 larvae/100 plants, in addition to untreated and Helicoverpa infestation free as control...
Management of Insecticide Resistant Helicoverpa armigera Lepidoptera: Noctuidae) in Cotton in India
1998
Helicoverpa armigera (Habner) was responsible for some $500 million of damage in India in the 1997-8. Insecticide resistance levels have been monitored routinely at sites throughout the countl)' since 1992 using discriminating dose assays. Resistance to pyrethroids is ubiquitous and stable at around 50-80% in most areas. Organophosphate and endosu(fan resistance is stable at around 20-50%. Carbamate resistance is low. There is-.... (ll:. rrently no significant resistance to Bt. Putting in place eff ective, economic, insecticide-based programmes that do not exacerbate the resistance problems, is a priority. Field trials from 1992-5 at 1CR1SAT developed appropriate 1PMI1RM practices in pigeonpea Clnd cotton. In 1995-6 these were takell illto 'split-plot' 1PMIIRM farmer trials in Andhra Pradesh (AP). Seed cotton yields were slightly enhanced with a 23% reduction in the number oj insecticide sprays and a 57% reduction in the a.i. applied. In expanded trials in 1996-7 trials in AP and Tamil Nadu, insecticide use was reduced by over 40% and yields enhanced by 30%. Components of the package included appropriate varietal selection, seed quality and agronomy and improved spraying practices with quality materials based on scouting to simple economic thresholds. Early season spraying for sucking pests was avoided by the use of systemic seed dressings. The sequence used for bollworms was: Eggs: at low numbers-neem; at high numbersprofenojos, Larvae: 1st round: endosulfan; 2nd round OPs (quinalphos or chlorpyrifos); 3rd round,' carbamates (carbaryl); 4th round-pyrethroids (cypermethrin, fen valerate. deltamethrin or lambda cyhalothrin). In the 1997-8 season farmer participatol)' demonstrations were undertaken in four states (Punjab, Andhra Pradesh, Maharashtra and Tamil Nadu). In all areas spray applications were at least halved with respect to non-participating farmers' and yields rose by at least a third. The work was expanded in the 1998-9season. The nationwide monitoring of insecticide resistance in Helicoverpa armigera by the collaborating laboratories of the Indian Council for Agricultural Research (I CAR) National Helicoverpa Network is reported in Regupathy et al. (this volume) and our current understanding of the mechanisms underlying the resistance by Kranthi (also this volume). Details
1990
Helicoverpa (Heliothis) armigera Hubner (Lepidoptera: Noctuidae) is a major pest of several food and cash crops in the Old Wor ld semi-arid tropics. In this publication, scientists review research on the host selection behavior of H. armigera and on the mechanisms of host-plant resistance to this pest in pigeonpea (Cajanus cajan (L.) Millsp.) and chickpea (Cicer arietinum L.). Five technical papers cover host selection by lepidopteran insects, behavioral and electrophysiological studies of H. armigera, the identification of host-plant resistance in pigeonpea and chickpea, and the chemical basis of pest resistance in these pulse crops. Recommendations are made for further action to control H. armigera through a better understanding of its host selection behavior and the factors that interfere wi th this behavior.
How do susceptible Helicoverpa larvae behave on Bollgard II ?
2011
tion of Bollgard II cotton in Australia there were reports that Helicoverpa larvae were surviving in these crops at levels that exceeded the recommended threshold levels for control. In response to these reports, Crop Consultants Australia members were surveyed for data from the 2005–06, 2006–07, and 2007–08 seasons (see the June 2009 issue of The Australian Cottongrower for a full report). This work showed that in any year an average of 15 per cent of the Bollgard II area planted carried larvae at above threshold levels, and that survivors were present in some fields in all cotton growing regions. Survival always occurred during flowering, and could follow low or high egg pressure but was always within the range of one to three larvae per metre. Within a region, survivors were localised to particular fields, and within a field the distribution of larvae could be uniform or patchy. But in general only between 20– 60 per cent of plants in a field sustained damage from surviving larva...