Muhammad Razaq

Evidence of Field-Evolved Resistance to Organophosphates and Pyrethroids in Chrysoperla carnea (Neuroptera: Chrysopidae)

Abstract The toxicity of some of the most commonly used insecticides in the organophosphate and pyrethroid classes were investigated against different Chrysoperla carnea (Stephens) (Neuroptera: Chrysopidae) populations collected over three consecutive years (2005–2007). The populations were tested using leaf dip bioassays for residual effects and topical applications to measure the response of larvae that would come into direct contact with field application of insecticides. In leaf dip assays, the LC50 (micrograms per milliliter; 120 h) values for chlorpyrifos and profenofos were in the range of 59.3–1,023 and 180.02–1,118 respectively. The LC50 values for lambda-cyhalthrin, alphamethrin, and deltamethrin were 359.08–2,677, 112.9–923.5, and 47.81–407.03, respectively. The toxicity for the above insecticides in topical application was similar to toxicity in leaf dip assays. The susceptibility of a laboratory population, which was locally developed and designated as (Lab-PK), to deltamethrin was comparable with another susceptible laboratory population. Resistance ratios for five field populations were generally low to medium for deltamethrin, but high to very high for chlorpyrifos, profenofos, lambda-cyhalthrin and alphamethrin compared with the Lab-PK population. Our data also suggested that the five field populations had multiple resistance to two classes of insecticides. The populations showed resistance to two organophosphates tested and to lambda-cyhalthrin and alphamethrin; however, resistance to deltamethrin was only found at two locations. This pattern indicates occurrence of two divergent patterns of resistance within pyrethroids. The resistance to the insecticides was stable across 3 yr, suggesting field selection for general fitness had also taken place in various populations of C. carnea. The broad spectrum of resistance and stability of resistance to insecticides in C. carnea in the current study suggested that it could be a prime candidate for mass releases and compatible with most spray programs.

A cross sectional survey of knowledge, attitude and practices related to house flies among dairy farmers in Punjab, Pakistan

BackgroundHouse flies are of major public health concerns in areas with poor sanitation and hygienic conditions. Unfortunately, sanitation and hygiene have always been ignored in dairy farms particularly in the developing or low-income countries. Management of these flies mostly depends on the awareness regarding associated hazards and protective measures taken by the people to minimize risks associated with flies. The present study therefore explores the knowledge, attitude and practices taken by dairy farmers in Punjab, Pakistan against house flies.MethodsThe present study was based on a cross sectional self administered survey to a convenience sample of 173 small scale dairy farmers in four localities – Multan, Lahore, Shorkot and Faisalabad – of Pakistan. The relationships between socio-demographics, knowledge and preventive practices were investigated through logistic regression analysis and chi-square test of association.ResultsConsiderable number of dairy farmers 71/173 (41.04%) had no idea about the problems associated with house flies. Although 77/173 (44.51%) dairy farmers reported house flies as disease transmitters, only 23 (29.87%) farmers were familiar with diseases and 22 (28.57%) had somewhat idea of the mode of disease transmission. We found a positive association between dairy farmer’s education level and overall knowledge of house flies in multivariate analysis. Farmer’s education level and knowledge of the house flies breeding sites had a positive association with the adoption of house fly prevention practices by the respondents. However, knowledge of the problems associated with house flies and preventive measures had no association with house fly prevention practices.ConclusionThe present ethnoentomological survey provides information about knowledge, attitude and practices of dairy farmers related to house flies in Punjab, Pakistan. We conclude that the farmers’ education level and knowledge of the breeding sites had a positive association with the adoption of prevention practices against house flies. The study also highlights the need of targeting the lack of knowledge of dairy farmers for the successful management of house flies.

Increased fitness and realized heritability in emamectin benzoate-resistant Chrysoperla carnea (Neuroptera: Chrysopidae)

The common green lacewing Chrysoperla carnea is a key biological control agent employed in integrated pest management (IPM) programs for managing various insect pests. A field collected population of C. carnea was selected for emamectin benzoate resistance in the laboratory and fitness costs and realized heritability were investigated. After five generations of selection with emamectin benzoate, C. carnea developed a 318-fold resistance to the insecticide. The resistant population had a relative fitness of 1.49, with substantially higher emergence rate of healthy adults, fecundity and hatchability and shorter larval duration, pupal duration, and development time compared to the susceptible population. Mean population growth rates; such as the intrinsic rate of natural population increase and biotic potential were higher for the emamectin benzoate selected population compared to the susceptible population. The realized heritability (h2) value of emamectin benzoate resistance was 0.34 in emamectin benzoate selected population of C. carnea. Chrysoperla species which show resistance to insecticides makes them compatible with those IPM systems where emamectin benzoate is employed.

Fitness cost and realized heritability of resistance to spinosad in Chrysoperla carnea (Neuroptera: Chrysopidae).

The common green lacewing Chrysoperla carnea is a key biological control agent employed in integrated pest management (IPM) programs for managing various insect pests. Spinosad is used for the management of pests in ornamental plants, fruit trees, vegetable and field crops all over the world, including Pakistan. A field-collected population of C. carnea was selected with spinosad and fitness costs and realized heritability were investigated. After selection for five generations, C. carnea developed 12.65- and 73.37-fold resistance to spinosad compared to the field and UNSEL populations. The resistant population had a relative fitness of 1.47, with substantially higher emergence rate of healthy adults, fecundity and hatchability and shorter larval duration, pupal duration, and development time as compared to a susceptible laboratory population. Mean relative growth rate of larvae, intrinsic rate of natural population increase and biotic potential was higher for the spinosad-selected population compared to the susceptible laboratory population. Chrysoperla species are known to show resistance to insecticides which makes the predator compatible with most IPM systems. The realized heritability (h 2) value of spinosad resistance was 0.37 in spinosad-selected population of C. carnea.

Impact of neonicotinoid seed treatment of cotton on the cotton leafhopper, Amrasca devastans (Hemiptera: Cicadellidae), and its natural enemies

BACKGROUND Neonicotinoid seed treatments suppress populations of pest insects efficiently and can enhance crop growth, but they may have negative effects on beneficial arthropods. We evaluated the effects of either imidacloprid or thiamethoxam on the abundances of a sucking pest, the cotton leafhopper (Amrasca devastans), and its arthropod predators under field conditions. We also evaluated the impact of seed treatment on transgenic cotton plant growth, with pests and natural enemies present or absent. RESULTS Imidacloprid and thiamethoxam reduced pest abundance, with greater effects when dosages were higher. Treatment at recommended doses delayed the pest in reaching the economic damage threshold by around 10-15 days (thiamethoxam) and 20 days (imidacloprid). Recommended doses also enhanced plant growth under all tested conditions; growth is affected directly as well as via pest suppression. Neonicotinoid applications reduced abundance of beneficial arthropods, with lower populations after higher doses, but negative effects of imidacloprid were not apparent unless the manufacturer-recommended dose was exceeded. CONCLUSION Imidacloprid applied at the recommended dose of 5 g kg(-1) seed is effective against A. devastans and appears to be safer than thiamethoxam for natural enemies, and also enhances plant growth directly. We caution, however, that possible sublethal negative effects on individual beneficial arthropods were not evaluated.

Arthropod Fauna of Brassica Napus and Brassica Juncea from Southern Punjab (Pakistan)

Cultivation of oilseed brassicas in the Indian Sub-continent date back from 2000 to 1500 B.C. These crops are an important source of edible oil, with current local production of edible oil in Pakistan accounting for 31% with the remaining 69% met through imports. Damage due to insect pests is a major constraint to production of these crops. In Pakistan 70–80% losses in yield have been reportedly due to aphids in these crops in other parts of country (Rustamani et al., 1988). We have been surveying these crops since the mid 1990s. Insect pests and natural enemies were recorded on a weekly basis from the end of November to the end of March at Multan, Bahawalpur and Dera Ghazi Khan are 100 km away from Multan. Populations of aphids were recorded by beating the top 10 cm of the central inflorescence of plants gently 10 times with a 15 cm stick (of pencil thickness). Aphids were collected on a piece of white sheet and counted. Populations of predators were noted on a per plant basis. No arthropods other than insects were observed during the study. Specimens occasionally sampled from time to time have been deposited in the Canola Laboratory at the University College of Agriculture, Bahauddin Zakariya University, Multan (Pakistan). Cabbage aphid, Brevicoryne brassicae (L.) and turnip aphid, Lipaphis erysimi (Kaltenbach) were continuously observed as the most abundant among all insects observed. Only a few plants of B. napus were found to be infested by Myzus persicae (Sulzer) during 2003 at Multan. Population of the cabbage aphid were always greater in abundance than that of turnip aphid on B. napus and B. juncea. Other insects recorded were the sawfly, Athalia lugens (Klug) (Hymenoptera: Tenthredinidae), Spodoptera litura L., Helicoverpa armigera (Hubner) (Lepidoptera: Noctuidae) and the whitefly, Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae). A. lugens feeds upon the leaves by making holes. No insect other than B. brassicae and L. erysimi were observed to cause economic damage on crops sown timely, i.e., last week of October and onward. However, S. litura and B. tabaci severely damaged the crops sown early, i.e., mid-October in years when outbreaks occurred on cotton. Cotton is an important source to these two species of insects, and both of these insects are a threat to very early sown oilseed

Identification of Plant Semiochemicals and Characterization of New Olfactory Sensory Neuron Types in a Polyphagous Pest Moth, Spodoptera littoralis

Phytophagous insects use blends of volatiles released from plants to select hosts for feeding and oviposition. To behaviorally analyze complex blends, we need efficient and selective methods for elucidating neuron types, their ligands, and specificity. Gas chromatography-combined single sensillum recordings (GC-SSRs) from antennal olfactory sensilla of female moth, Spodoptera littoralis revealed 38 physiologically active peaks in the headspace volatile blends from both larvae-damaged cotton plants and lilac flowers. Using GC-combined mass spectrometry, 9 new physiologically active compounds were identified from damaged cotton and 11 from lilac compared with earlier electrophysiological studies using antennae of female S. littoralis. We characterized 14 novel classes of olfactory sensory neurons (OSNs). Among these, we found the first 2 ligands for a frequent type of short trichoid sensillum, for which no ligands were identified earlier. By using GC-SSR, a substantial increase in functional classes of OSNs and active compounds, 40% and 34% more, respectively, compared with recent studies using GC-electroantennogram or SSR using single compounds was detected. Compared with the estimated number of corresponding antennal olfactory receptors, the OSN classes now correspond to 83% of a likely maximum. The many specialist OSNs observed may facilitate behavioral confirmation of key plant volatiles in blends.

Effect of rotational use of insecticides on pyrethroids resistance in Helicoverpa armigera (Lep.: Noctuidae)

Abstract:  To investigate fluctuation in susceptibility to insecticides in the field, natural populations of Helicoverpa armigera were collected from the same field in the region of Multan, Pakistan in 2002 and 2003. The populations were examined against pyrethroids (viz. cypermethrin, esfenvalerate and fenpropathrin) and new insecticides (viz. spinosad, abamectin and indoxacarb). In 2002, the resistance ratio (RR) of cypermethrin and esfenvalerate was significantly higher than fenpropahrin compared with susceptible population. The susceptibility to cypermethrin, esfenvalerate and fenpropathrin increased significantly in 2003; however, the RR for cypermethrin was about half the RR (38) of esfenvalerate (101) and fenpropathrin (89). The toxicity of spinosad, abamectin and indoxacarb was identical in both years. In the field experiments, abamectin was more effective than other compounds tested whereas fenpropathrin, cypermethrin and esfenvalerate had similar toxicity. These results might have important implications in resistance management and suggest that the rotational use of spinosad, abamectin and indoxacarb could help to avoid the development of multiple resistant in H. armigera.

Biological trait analysis and stability of lambda-cyhalothrin resistance in the house fly, Musca domestica L. (Diptera: Muscidae)

House flies, Musca domestica L., (Diptera: Muscidae), are pests of poultry and have the ability to develop resistance to insecticides. To design a strategy for resistance management, life history traits based on laboratory observations were established for lambda-cyhalothrin-resistant, susceptible and reciprocal crosses of M. domestica strains. Bioassay results showed that the lambda-cyhalothrin-selected strain developed a resistance ratio of 98.34 compared to its susceptible strain. The lambda-cyhalothrin-selected strain had a relative fitness of 0.26 and lower fecundity, hatchability, lower number of next generation larvae, and net reproductive rate compared with its susceptible strain. Mean population growth rates, such as intrinsic rate of population increase, and biotic potential were lower for the lambda-cyhalothrin-selected strain compared to its susceptible strain. Resistance to lambda-cyhalothrin, indoxacarb, and abamectin was unstable while resistance to bifenthrin and methomyl was stable in the lambda-cyhalothrin-selected strain of M. domestica. Development of resistance can cost considerable fitness for the lambda-cyhalothrin-selected strain. The present study provided useful information for making potential management strategies to delay resistance development in M. domestica.

Damage Patterns, Monitoring, and Management of Procontarinia mangiferae (Diptera: Cecidomyiidae) in Pakistan

Since 2005, mango has been damaged by a group of new pests, the gall midges, in all mango-growing areas of Pakistan. Little is known about these pests in Pakistan. In this report, we present information on the occurrence, damage patterns, methods for monitoring, and management of Procontarinia mangiferae (Felt), a mango gall midge found in the country. At the study site (Rahim Yar Khan, a district of the province Punjab, Pakistan), the pest was active from January/February to April as eggs, larvae, and adults on mango inflorescence buds, branches (axillaries), and immature fruits. Females of P. mangiferae oviposited in inflorescence tissues, and larvae, after feeding on plant tissues, dropped to the soil under the mango trees for pupation from February to April. Mango trees in commercial orchards were more heavily damaged by P. mangiferae than were isolated trees in farmer fields (66.7%). The adults of P. mangiferae were captured on sticky traps of all tested colors, and were in flight from January to May. Captures per trap were highest on yellow traps, followed by green, blue, and clear traps. Control of mango gall midge was effectively provided by the synthetic insecticide bifenthrin (Talstar 10 EC) and also by application of neem seed kernel extract on the tree canopy if integrated with raking the soil under the mango tree canopy.