Adult Myzus Persicae Research Articles

Reciprocal effect of ethyl formate and phosphine gas on two quarantine pests, <i>Tetranychus urticae</i> (Acari: Tetranychidae) and <i>Myzus persicae</i> (Hemiptera: Aphididae)

Fumigation of fruits and vegetables during quarantine and pre-shipment (QPS) treatment should be effective with a shorter fumigation time to minimize phytotoxicity. In this research study, a shorter fumigation time, 2 hours exposure which is shorter than that of the current commercial fumigation procedures using a lower dose of ethyl formate (EF) mixed with phosphine (PH3) on strawberry was investigated. The reciprocal effect between EF and PH3 against nymphs and adult Myzus persicae (Sulzer) and Tetranychus urticae (Koch) was evaluated. In addition, L(Ct)50 and L(Ct)99 of EF only and EF mixed with PH3 were analyzed at 5°C and 20°C. The synergistic ratio (SR) of L(Ct)50 and L(Ct)99 for the nymph and adult stages of M. persicae were >1.0, which indicated a synergistic effect between EF and PH3. However, the SR values of L(Ct)50 and L(Ct)99 of the nymph and adult stages of T. urticae were ≤1.0 indicating that there was no synergistic effect between the two fumigants against T. urticae. Our results showed that the reciprocal effect between EF and PH3 has different effects on M. persicae and T. urticae. This could be attributed to the biological and physical differences between the class Arachnida and Insecta. The synergistic effect between EF and PH3 against M. persicae within a shorter exposure period and without phytotoxicity on fruits and vegetables will significantly benefit the horticultural industry.

Conjugation of δ‐endotoxin from Bacillus thuringiensis with abamectin of Streptomyces avermitilis as a new type of biocide, GCSC‐BtA, for control of agricultural insect pests

AbstractConjugation of δ‐endotoxin from Bacillus thuringiensis with abamectin, a toxin of Streptomyces avermitilis, was carried out to form a new type of biocide, GCSC‐BtA based on “Germany‐China Scientific Cooperation” research, for the control of agricultural insect pests. The strategy for biochemical linkage was designed by conjugating an amino group in B.t. protoxin with a carboxyl group in carboxylated abamectin under the treatment of conjugator EDC [1‐Ethyl‐3‐(3‐dimethylaminopropyl carbodiimide Hydrochloride)]. The formation of B.t. protoxin was processed by solubilizing B.t. crystal in 25 mM dithiothreitol (DTT) at 37 °C for 2 h. The carboxylated abamectin was formed by carboxylating the NaH‐activated abamectin with 10 mg/ml butyric anhydride at 111 °C in a water‐circumfluent condensation device for 2 h. The conjugating reaction, consisting of 5 mg/ml B.t. protoxin, 10 mg/ml carboxylated abamectin and 19.17 mg/ml EDC, was successfully conducted at room temperature for 24 h. Significant differences were found between pure abamectin, carboxylated abamectin and the conjugated BtA by means of UV‐photo absorptions recorded at wavelengths 354, 438, 518, 600 nm (P < 0.01). LT50 of the conjugated GCSC‐BtA to the 3rd instar larvae of Plutella xylostella (L.) (Lep., Plutellidae) was 35.27 μg a.i./ml, about 62 % and 76 % of that caused by the B.t. protoxin and the caxboxylated abamectin, respectively. The conjugated GCSC‐BtA caused 87.14 % mortalities in larvae of P. xylostella, 93.75 % in adult Myzus persicae (Sulzer) (Hom., Aphididae) and 89.33 % in adult Phyllotreta vittata Fabricius (Col., Chrysomelidae) as compared to 48.33 % by the B.t. crystal only in P. xylostella. The symptoms caused by conjugated GCSC‐BtA in the 3rd instar of P. xylostella were black color in the head part and white‐yellow in the abdomen of dead larvae, which differed from the black color or the white‐yellow all along the body caused by either the B.t. crystal or the abamectin, respectively. It was concluded that the conjugated GCSC‐BtA biocide had a broader host spectrum and a faster killing speed than either the B.t. crystal or abamectin alone for the control of agricultural pests.

Potter Spray Tower Bioassay of Selected Citrus Pests to Petroleum Spray Oil

ABSTRACTA Potter spray tower was used to determine the relative susceptibility of selected stages of various citrus pests and green peach aphid to petroleum spray oils. the order of decreasing susceptibility, expressed as μg oil/cm2 required to give 95% mortality, was first‐instar Saissetia oleae (Olivier) 41, first‐instar Ceroplastes sinensis Del Guercio 46, adult Myzus persicae (Sulzer) 50, first‐instar Aonidiella aurantii (Maskell) 55, first‐instar C. destructor Newstead 59, first‐instar C. rubens Maskell 59, adult Panonychus citri (McGregor) 71, adult Heliothrips haemorrhoidalis (Bouché) 74, first‐instar Pseudococcus calceolariae (Maskell) 135, adult Tetranychus urticae Koch 166, adult Toxoptera citricida (Kirkaldy) 241, prepupal H. haemorrhoidalis 351, and adult P. calceolariae 1075. the validity of the technique and the relevance of the results to practical field application are discussed in terms of a phytotoxicity threshold of 150 μg oil/cm2.

Systemic antifeedant effects of azadirachtin on the peach‐potato aphid Myzus persicae

AbstractThe electrical penetration graph (EPG) method was used to analyse the feeding behaviour of apterous, adult Myzus persicae (Sulzer) (Homoptera: Aphididae) on Nicotiana clevelandii (Gray) seedlings, treated systemically with azadirachtin. A preliminary experiment showed that the effects of tethering aphids for EPG recording were minimal. The percentage of the 9 h recording period devoted to non‐penetration activities, and to stylet pathway patterns increased as the azadirachtin concentration in the root treatment increased. The number of probes initiated, and the numbers of sieve tube penetrations also increased with increased azadirachtin concentration. The mean time elapsing between the initiation of the first probe to reach a sieve element and contact with this tissue was not significantly altered by azadirachtin treatment. However, azadirachtin treatment significantly reduced the percentage of probes that reached sieve elements and increased non‐penetration activity before and after the first period of ingestion from the sieve elements. The percentage of the recording period spent in the EPG pattern associated with sieve tube penetration was significantly reduced by an azadirachtin concentration of 300 ppm, and the duration of each individual penetration was significantly reduced by an azadirachtin concentration of 100 ppm. When the total EPG was split into 3 h periods, significant interactions were seen between time period and azadirachtin concentration for the duration of non‐penetration, pathway, and sieve tube penetration patterns.

Low temperature mortality of the peach‐potato aphid Myzus persicae

ABSTRACT. The mean supercooling points of first instar and adult Myzus persicae (Sulzer) maintained at 20°C and cooled at 1°C min−1 were −26.6 and −25.0°C respectively. The LT50 (temperature) of the same age groups drawn from the same population and cooled at the same rate were −8.1 and −6.9°C, indicating extensive pre‐freeze mortality in M.persicae under laboratory conditions. Acclimation at 10 and 5°C did not affect supercooling but depressed the LT50 of both first instars and adult aphids. Freezing of leaves during feeding did not increase mortality above that expected from the direct effects of low temperature. The level of cold in different winters can be expressed in terms of the total number of frost days, and the frequency of abnormally cold days. Winter temperatures differ markedly in a vertical profile from the soil to the soil or grass surface, and then to the air (and foliage) above. The time of the first record of M.persicae in suction trap samples is correlated with January and February temperatures except in the west of England and Wales. Further north December and January temperatures are relatively more important. Winter temperatures and the resultant aphid mortality is a primary determinant of the timing of the spring migration.

Variation in Myzus persicae (Sulz.) (Hemiptera, Aphididae) reared on different host-plants

Apterous adult Myzus persicae (Sulz.) of a glasshouse strain differed greatly in their ability to colonise sugar-beet according to the plant on which they and their forebears were cultured. Those from Chinese cabbage (Brassica pekinensis) settled least readily on beet, whilst aphids from broad beans (Vicia faba) produced larger populations than those cultured on sugar-beet. When reared wholly on groundsel (Senecio vulgaris) young adults differed in their ability to colonise Chinese cabbage, sugar-beet and broad bean according to their parents' culture host species, and these differences were detected in a second generation reared wholly on groundsel. The responses of clones isolated from cultures maintained continuously on Chinese cabbage and broad bean were similar, showing that the effect was caused by the aphids' host-plant experience, and was not due to fixed, heritable characters of the sub-cultures. Some, but not all clones of M. persicae collected from the field showed enhanced colonising ability after culture on broad bean as compared with Chinese cabbage. This was apparent on sugar-beet and lettuce (Lactuca sativa). These effects of former hosts on the ability of M. persicae to colonise plants may be important both in work on resistance to aphids and in the epidemiology of aphid-borne diseases.

Dietary Amino Acid Requirements of the Aphid Myzus persicae Affected by Antibiotic Uptake

Plant-reared, apterous adult Myzus persicae were allowed to feed on synthetic diets with and without 0.01% aureomycin, and their progenies raised on antibiotic-free diets from which single amino acids were omitted. The individual omission of all 10 “essential” amino acids from diets fed to larvae derived from the antibiotic-treated mothers resulted in a considerable reduction in larval growth. Larvae derived from mothers fed an antibiotic-free diet exhibited such a reduction only when fed histidine-, isoleucine-, or methionine-free diets. In contrast, the individual omission of the “nonessential” amino acids did not affect the growth of larvae whether they were derived from mothers fed antibiotic-free diet or from mothers fed the diet containing aureomycin. The results suggest that the symbiotes of M. persicae supply the aphid with most of the essential amino acids in amounts sufficient for growth, when these nutrients are inadequately or not available to the aphids in their food. No improvement in the growth of larvae from antibiotic-treated mothers was obtained by incorporating lipid extracts of aphids or cholesterol into “complete” diets, in attempts to supply the aphids with dietary sterol.

Assimilation by Apterous Adult Myzus persicae Maintained on a Synthetic Diet

The weights of individual adult apterous Myzus persicae (Sulzer), allowed to feed on a 20% sucrose solution or on a complex diet, were recorded daily, as were the number of larvae and total weight of the larvae deposited by each aphid. By adding to the weight of each adult aphid the weight of all the larvae it had deposited, a daily “cumulative weight” value was obtained. Ignoring slight variations in weight occurring during the first day of the experiment, on the diet, the mean cumulative weight increased during the test period (6 days), whereas the mean adult weight remained constant; on 20% sucrose the mean cumulative weight remained constant, whereas mean adult weight declined. Evidently assimilation occurred on the diet but not on sucrose during a period when larviposition on both treatments was in progress.

Transmission of potato leaf roll virus by three species of aphids

This paper reports the experimental results on the transmission of potato leaf roll virus by three species of aphids.Virus-free, apterous, adult Myzus persicae Sulz. fed on plants infected with potato leaf roll virus for more than 3 days, transmitted the virus to 50-90per cent of healthy seedlings of Physalis floridana Rydb. when the aphids were tested individually. Rate of transmission was enhanced by increasing the number of the aphid during test feeding. The P. floridana plant infected for two weeks seems to be sufficient as a source of the virus.In order to determine the effect of temperature on the infection, P. floridana plants were inoculated and kept at 18° and 13°C for one month. The plants produced symptoms at 18°C but no symptom was observed at 13°C with the exception of one test plant which developed symptoms 10 days after transferring to greenhouse.The transmission rate by both aphid vectors Aulacorthum matsumuraeanum Hori and Macrosiphum euphorbiae Thom. was 10 to 20per cent when the aphids were tested individually, indicating that both species were inefficient as the vector as compared with M. persicae.

THE USE OF SOIL INSECTICIDES TO CONTROL POTATO APHIDS AND VIRUS DISEASES

A replicated trial was done to find whether the insecticides Thimet and Rogor applied in the soil affected the spread of aphid‐transmitted viruses from infected to healthy plants with potato crops. The insecticides were applied at planting as activated carbon formulations at rates equal in cost to three sprays with DDT emulsion at 2 lb. DDT per acre. The infected plants were removed (rogued) in late June.Thimet applied along the furrows with the fertilizer, and Rogor applied in individual doses beneath each tuber, kept the plants free from aphids from a week after the plants emerged until early August. Thimet in individual doses was less effective but greatly decreased the aphid infestation. All treatments prevented or greatly decreased the spread of leaf‐roll virus, but they only slightly decreased the spread of virus Y. No treatment damaged the plants or depressed yields significantly.Tubers harvested from the plots treated with insecticides contained only very small quantities of the insecticides, but shoots from them, when infested with adult Myzus persicae (Sulz.), carried fewer aphids a week after infestation than did shoots from control tubers. Shoots of tubers from treated plots also grew more slowly than those from the controls.The aphicidal efficiency of Thimet applied as individual doses separated from the tubers by distances of up to 6 in., decreased as the distance increased, but the effect of distance became less as time passed.Reasons for the differences in the behaviour of the insecticides are discussed, and the possibilities that the method offers to control virus diseases. The application of insecticides to soil promises to be a useful way of controlling the spread of viruses, provided the harvested crop is free from toxic residues.