Activity ofBacillus thuringiensis Berl. on the lesser cotton leafwormSpodoptera exigua Hbn. (Lep., Noctuidae) in corn and sunflower cultivations in Egypt

Field applications usingBacillus thuringiensis (Dipel 2 X) againstSpodoptera exigua infesting corn and sunflower cultivations were carried out in two different localities in Egypt. The percentage of infested corn plants decreased to 2.5%, seven days after treatment with Dipel 2x, (250 g/fed) and the yield was significantly increased compared with untreated plots. The carbamate insecticide (Lannate) at 300 g/fed caused complete kill to the larvae and the highest yield was obtained. Application of Lannate, Dipel (250 g) or a combination of both (150 g/each/fed) caused a high reduction of the larvae existing in sunflower after seven days from application, while Dipel at 200 g/fed gave a lower effect. Ten days after application, the number of larvae and infested plants increased significantly in plots treated with Lannate alone, while plots treated with either Dipel (250 g) or Dipel combined with Lannate (150 g/each) still maintained a lower infestation. The estimated yield showed the highest increase in plots treated with Lannate followed by Dipel (250 g) and then a combination of both.     

Evaluation of microbial and chemical insecticides for the control ofSpodoptera exigua (Lep., Noctuidae) on soybean plants

Field experiments have been carried out to evaluate the potency of the biological control agentBacillus thuringiensis (Dipel), the pyrethroid Fenvalerate and their combinations for the control of the lesser cotton leafwormSpodoptera exigua on soybeans in Qualubia governorate. Molasses was combined with all treatments to enhance their effectiveness. One spray application with either Dipel or Fenvalerate showed an obvious reduction in larval counts ofS. exigua, associated with a significant increase in the crop yield but in varying degrees, in correlation with the tested dose. Treatments with combinations of both biological and chemical insecticides at the lowest tested doses (62 g ofB. t. +50 ml of Fenvalerate/feddan) showed to be highly potential, and caused 2.8 fold increase in the crop yield. It may be recommended that a combination of both preparations may be used for the control ofS. exigua.     

Zur Wirkung zweier Juvenilhormon-Analogen auf die Baumwolleule Spodoptera littoralis (Boisd.) (Lep., Noctuidae)

Effects of two juvenile hormone mimics on the Egyptian Cotton Leaf-Worm, Spodoptera littoralis (Boisd.) (Lep., Noctuidae) Two analogues of insect juvenile hormone were tested for effects on eggs, 6th instars, and pupae ofSpodoptera littoralis (Boisd.). These were 3,7-dimethyl-6-epoxy-2-nonene-1-oxy (3,4-methylene-dioxybenzene), and 3,7-dimethyl-6-epoxy-2-nonene-1-oxy (4-chlorobenzene). The purpose was to observe effects of these chemical on fecundity, metamorphosis, and survival. Against 24-hour-old eggs the chloro-derivative was much more potent inhibitor of embryonic development than its methylene dioxy-analogue. Against 6th instar larvae these two compounds were equipotent in resulting intermediate forms incapable of survival. Against pupae these two analogues at 6–8 g/insect caused deformities and reduced fecundity and fertility of the survival adults to more than 90% of their normal levels.     

Wirkungen von zwei Insektenwachstumshemmern auf die Eiablage und Eier vonHeliothis armigera (Hb.) (Lep., Noctuidae)

The effect of two insect growth inhibitors (PH-6040 and H-24108) on the fecundity, hatchability, viability and sterility of eggs laid by treatedHeliothis armigera female moths had been studied. Moths treated with these compounds laid less number of eggs than untreated moths. The egg laying capacity decreased as the concentration of any compound increased and vice versa. The same trend could be applied for egg hatchability and sterility as being affected by insect growth inhibitors and their concentrations.     

Field evaluation of the potency ofBacillus thuringiensis on lepidopterous insects infesting some field crops in Egypt

Agrotis ypsilon andSpodoptera littoralis can be successfully controlled on various field crops usingBacillus thuringiensis (Dipel 2X) baits and sprays. Baits based on the pathogen at 200–250 g/Feddan, scored the best efficacy againstA. ypsilon in clover fields followed by potato, tomato, and cotton cultivations. Addition of some chemical additives (inorganic salts) toB. thuringiensis bait formulations greatly enhanced its potency. This was associated with an obvious increase in the yield of clover, potato and tomato crops; calcium oxide showed to be highly afficient in this respect. Sprays of Dipel 2X were also found as affective as lannate in controllingS. littoralis on clover cultivations.

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Zusammenfassung Die Untersuchungen ergaben, daßAgrotis ypsilon undSpodoptera littoralis an verschiedenen Feldfrüchten erfolgreich mitBacillus thuringiensis (Dipel 2X) als Köder oder Sprühmittel bekämpft werden können. Die Köder auf der Grundlage von 200–250 gBacillus/Feddan erzielten die besten Ergebnisse gegenA. ypsilon auf Kleefeldern, gefolgt von Kartoffel, Tomate und Baumwolle. Die Beimengung von chemischen Zusatzmitteln (anorganische Salze) zu denBacillus-Ködern erhöhte die Wirksamkeit beträchtlich. Daraus resultierte eine auffallende Steigerung der Klee-, Kartoffel- und Tomatenernte. Dabei war Kaliumoxid das wirksamste Zusatzmittel. Das Sprühen mit Dipel 2X erwies sich in Kleefeldern als ebenso wirksam wie die Anwendung des chemischen Pestizids Lannate.

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With 4 tables     

Zur Wirkung der Nahrungspflanze auf die Entwicklung und Vermeharung der Baumwolleule,Spodoptera littoralis (Boisd.) (Lep.,Noctuidae)

Effect of some host plants on development and reproduction of Spodoptera littoralis (Boisd.) (Lep., Noctuidae) Investigations were performed to study the effect of some hostplants on development and reproduction capacity of the Egyptian cotton leaf-worm,Spodoptera littoralis (Boisd,), Larval and pupal weights, life span, average number of eggs laid per female and percent digestability for fifth instar larvae were measured. Cotton leafworm was able to complete its life cycle only when reared on eigher castor bean leaves, clover, sweet potato leaves, or the outer green cabbage leaves. Chlorophyl-free inner white cabbage leaves, maize, and grape vine are nutritionally insufficient to support growth and development of larvae and, in turn, cause increase in span of survived larvae and none of these larvae metamorph to pupae. It seems that there is a positive correlation between larval and pupal weights and average number of eggs laid per female; the greater the weight of larvae and pupae the higher the number of eggs laid. Castor bean leaves seem to be the most favorable host plant for rearing cotton leafworm in the laboratory. The differences and variations in the growth and development of cotton leafworm due to feeding on different host plants are discussed.     

Wirkungen einesBacillus thuringiensis-Präparats und eines Juvenilhormon-Analogons über den Erdboden aufSpodoptera littoralis (Boisd.) (Lep.,Noctuidae)

Summary Sensitivy of Spodoptera littoralis (Boisd.) to soils treated with preparations of Bacillus thuringiensis and of a juvenil hormone analogue Various instar larvae ofSpodoptera littoralis were exposed to soil treated, with aBacillus thuringiensis-containing preparation (Bactospeine) and a juvenile hormone analogue (Ro 20–36 000).After treatment with Bactospeine, only high concentrations could affect emergence. Suppressed egg laying and sterility were the most marked effects. Also, the produced eggs were smaller in size.The juvenile hormone analogue showed high activity, particularly against freshly moulted 6th. instar larvae. Greater effects were elicited after ecposing the larvae to treated soil than to treated leaves for 48 hours. It appears to be fairly stable in soil. Its morphogenetic activity could be detected 60 days after application.     

Zum saisonalen Auftreten der Baumwolleule,Spodoptera littoralis (Boisd.) (Lep., Noctuidae) und ihrer Kernpolyedrose (NPV) in verschiedenen Distrikten Ägyptens

Infection rates of the nuclear polyhedrosis virus (NPV) in the cotton leafworm,Spodoptera littoralis larvae were assessed from 1985 through 1986 in clover fields at El-Behiera, El-Fayoum and El-Gharbia governorates. Infection rates of the pathogen were highest near the end of spring when the cotton leafworm larval populations were increasing. For the different governorates, the percentages of virus infection were almost higher in 1985-season than in 1986. El-Fayoum-larval population was the most infected by NPV followed by El-Gharbia and El-Behiera-populations, respectively. There was a positive correlation between infection rates of NPV on one hand, and density of larva and ambient temperature on the other.     

Ausweichnahrungspflanzen der Sojabohnen-Eule,Plusia orichalcea F. (Lep., Noctuidae) in Jabalpur,Indien

During an outbreak of the soybean semilooper,Plusia orichalcea F. in Jabalpur, the caterpillars not only caused heavy damages to the soybean crop but were also commonly feeding on many other plants growing in soybean fields and nearly bunds. A list of these alternative host plants containing 15 species of 6 families is given.     

Forecasting of outbreaks ofSpodoptera exempta Wik. (Lep., Noctuidae) based on sex-pheromone trapping in the republic of Yemen

Spodoptera exempta (Wlk.) is recorded every year in the Republic of Yemen. Based on the use of pheromone traps, a very simple but effectively applicable monitoring and forecasting system was developed. Areas from which infestations have been reported and the frequency of attacks are mapped in detail. The monthly distributions and frequencies of incidence are presented in two tables. The range of recordedS. exempta moths is illustrated and the number of outbreaks for the last 32 years described.     

Biological and ecological studies onDiadegma semiclausum Hellen (Hym., Ichneumonidae), a larval parasite of the Diamond-Back Moth,Plutella xylostella (L.) (Lep., Plutellidae) in Egypt

Diadegma semiclausum was reared in the laboratory on 2nd and 3rd instar larvae ofPlutella xylostella. At 25°C, the incubation period of the parasite's egg was 38h; the following stages lasted 5.4 days (5 instars), 33h (pre-pupa), and 5.9 days (pupa). Superparasitism occurred but only one parasite developed from one host larva. Sex ratio inD. semiclausum was found to be 11 in nature as well as in laboratory. The daily and total rate of eggs deposited per female were 13.6 and 164.2, respectively. The parasite male and female, fed on honey, lived for 11.2 and 14.6 days, respectively. Laboratory trials failed to rearD. semiclausum on certain lepidopterous larvae other thanP. xylostella. Percentages of parasitism byD. semiclausum inP. xylostella larvae collected from cabbage fields during 1982 ranged between 0 and 66%.

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Zusammenfassung Diadegma semiclausum wurde im Labor in L2- und L3-Raupen vonPlutella xylostella gezüchtet. Bei 25°C dauerte die Entwicklung 1,6 (Ei), 5,4 (L1–L5), 1,4 (Präpuppe) und 5,9 (Puppe) Tage. Superparasitismus kam vor, doch entwickelte sich nur jeweils eine Parasitenlarve. Das Geschlechterverhältnis vonD. semiclausum betrug im Freiland und im Labor 11. Die tägliche und die Gesamtzahl an abgelegten Eiern betrugen 13,6 und 164,2. Bei Fütterung mit Honig lebten die männlichen Parasiten i.M. 11,2, die weiblichen i. M. 14,6 Tage. Die Laborversuche zeigten, daßD. semiclausum sich ausschließlich ausP. xylostella-Raupen ziehen ließ. Die Parasitierungsquoten vonD. semiclausum inP. xylostella variierten bei Raupen von Kohlfeldern aus verschiedenen Landesteilen 1982 zwischen 0 und 66%.

     

Zur Wirkung einiger organischer Phosphor-Präparate in subletaler Dosis aufSpodoptera littoralis (Boisd.) (Lep. Noctuidae)

Zusammenfassung Das 4. Stadium der Larven von.S. littoralis wurde mit der maximalen nichtletalen Dosis (LD₀) sowie den subletalen Dosen (LD₁₀ und LD₅₀) der 3 Insektizide Cyolane, Monocrotophos und Phosvel im Laboratorium behandelt. Die überlebenden Individuen wurden bis zum Ausschlüpfen der Falter gezogen und anschließend auf ihre Biproduktion untersucht. Die max. LD₀ wirkte stimulierend auf die Eiproduktion, So betrug der prozentuale Anstieg der täglich abgelegten Eizahl je Weibchen in 5 Tagen 70,6% nach Cyolane-, 60,4% nach Monocrotophos- und 34,5% nach Phosvelbehandlung.Die subletalen Dosen wirkten unterschiedlich auf die Eiproduktion. Die LD₁₀ verursachte eine Vermindung, dagegen eine Erhöhung der Eizahl um 12,2% derung der Eizahl um 12,4% nach Cyolane-Anwenper female during 5 days was the following: 70,6%, nach Monocrotophos- und um 7,3% nach Phosvelanwendung. Die LD₅₀ verminderte die Eizahl um 34,6% bei Monocrotophos, führte dagegen bei Phosvel zu einem geringen Anstieg von 3,3%.Die LD₅₀ der 3 Insektizide hatte, verglichen mit der Kontrolle, eine Abnahme des Verpuppungsprozentes, eine Erhöhung der Sterberate bei den Larven und Puppen und eine Störung der Sexualrate zugunsten der mä nnlichen Falter zur Folge, während sich die max. LD₀ und LD₁₀ der o. g. Insektizide auf die Sexualrate, verglichen mit der Kontrolle, zugunsten der weiblichen Falter auswirkten. Im allgemeinen verhielt sich das Verpuppungsprozent umgekehrt proportional zur Insektiziddosis, während die Sterberate für Larven und Puppen proportional der Insektiziddosis war. Alle max. LD₀ hatten nur einen geringen Einfluß auf das Verpuppungsprozent.

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Summary The 4th instar larvae ofS. littoralis (Boisd.) was treated in the laboratory with the maximal non lethal dose (max. LD₀) and the sublethal doses (LD₁₀ and LD₅₀) of 3 insecticides (Cyolane, Monocrotophos and Phosvel). Surviving larvae reared to imagines, and then tested on the egg production. The max. LD₀ of the aforementioned insecticides showed a stimulation effect on the egg production of the females. The percentage of increase in the number of eggs produced 60,4%, 34,5% after Cyolane, Monocrotophos, and Phosvel treatment respect.The sublethal doses showed different effects on the egg production: LD₁₀ decreased the percentage of eggs of 12,4% after Cyolane treatment, while Monocrotophos and Phosvel increased the same (12,2% and 7,3% respect.). LD₅₀ decreased the percentage number of eggs (34,6% after Monocrotophos treatment) and there was a slight increase after Phosvel treatment (3,3%). LD₅₀ furthermore decreased the percent pupation, increased the mortality of the larvae and pupae and disturbed the sex ratio for the benefit of the males, compared with the control, while the max. LD₀ and LD₁₀ of the 3 insecticides affected the sex ratio for the benefit of the females. The percent pupation in general was in inverse relation to the insecticide dose, while the mortality of the larvae and pupae was in proportional relation to the insecticide dose. All max. LD₀ have shown a slight influence on the percent pupation compared with the Control.

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Faris El- Lakwah, Dozent, Polytechn. Institut Cairo, Dep. Agriculture, Moshtohor, A. R. E. — Farid A. Abdel-Salam, Ass.-Prof., Central Laboratory for Pesticides (CAPL), Ministry of Agriculture, Cairo-Dokki, A. R. E.     

Efficacy of aerial application ofBacillus thuringiensis to controlSpodoptera littoralis (Lepidoptera, Noctuidae) infesting soybean cultivations in Egypt

The calculated percentage of droplets deposition ofBacillus thuringiensis var.kurstaki HD-1 Dipel 2X on the foliage of soybean plants in relation to the sensitive “Ciba Geigy” papers showed to be the highest (92.4%) after ground spray application, compared to an average of 67.4, 85.8 and 89.3% following aerial application of the same preparation in spray volumes of 10, 20 and 30 l/F, respectively. Aerial application ofB. t. showed to be more effective during the first 3 days after spraying soybean cultivations and the mortality ofSpodoptera littoralis larvae varied between 36.9–67.2% in correlation to the spray volume. The volume achieving the highest and significant suppression of infestation was 20 l/F. On the other hand, the yield of soybeans obtained from plots receiving a spray volume of 30 l/F was higher compared to plots sprayed with a volume of 20 or 10 l/F, but with no significant difference when compared to those plots receiving ground spray application.     

Field tests on the efficacy of baits based onBacillus thuringiensis and chemical insecticides against the greasy cutwormAgrotis ypsilon Rdf. in Egypt

Field tests were conducted to determine the effectiveness of wheat-brain baits based onBacillus thuringiensis var.kurstaki HD-1 (dipel 2x) compared to the organophosphorous insecticide Hostathion against the greasy cutwormAgrotis ypsilon infestations on horse bean (Vicia fabae) cultivations. Significant larval reductions were observed in all treated plots after one application with a significant increase in the yield (1.45–1.60 folds) compared to the control plots. The yield was not obviously affected by varying the dose of dipel in the bait between 150–250 g/feddan. The addition of the adjuvant potassium carbonate to the dipel bait caused a significant larval reduction, 10 days after application and showed to be as efficient as baits based on Hostathion.     

Results and perspectives in the use ofBacillus thuringiensis Berl. var.kurstaki and other pathogens againstThaumetopoea pityocampa (Den. et Schiff.) in Italy (Lep., Thaumetopoeidae)

The pine processionary caterpillar,Thaumetopoea pityocampa is the most important defoliator of both native and introduced pines throughout Italy and is especially damaging in young plantations and on ornamental trees. A number of microbial pathogens have been isolated from larvae and pupae over the last 30 years. Some of them have been evaluated as biological control agents, and have provided encouraging results. However, onlyBacillus thuringiensis var.kurstaki (Btk) has passed the experimental screening and is now available for routine treatments, although its application by air is subjected to strict regulation by the government. The erratic performance of a single application ofBtk againstT. pityocampa that has been observed in the field (20–85% mortality) is related to a great variability in both the application dose and some population parameters ofT. pityocampa. The emergence period of adults varies from July (Alps) to October (South) and its duration is related to the spreading of the cohorts (individuals with different length of prolonged diapause) over time. In addition, embryonic development takes from 20 to 45 days, depending strictly on the temperatures recorded in the egg masses. As a result, the most vulnerable larval instars (L1 and L2) are never thoroughly reached by one application only, as the persistence of the bacteria on the needles is usually limited. Two applications are requested to control the pest in stands where the egg hatching occurs over more than one month. Another possibility consists of a single winter application against L3−L4 with a higher dose, to be performed where a certain amount of damage is tolerated.     

Integrated control of the solitary carpenter worm,Paropta paradoxa H.-Schaeff. (Lep., Cossidae) on fig trees in Egypt

According to the new trend of insect pests control in fruit orchards, biological in addition to mechanical control were evaluated for their efficiency on the reduction ofP. paradoxa population on fig trees during 1996, 1997 and 1998. Primary trials using the bacterial biopreparations of Delfin, Dipel and Bactospeine at the concentration of 200g/100 l. w. resulted in 81.8, 75.8 and 72.3% reduction of pest infestation, respectively. Pruning the infested branches, worming the larvae inside their tunnels and both mechanical treatments together along two successive years, reduced the infestation by 17.5, 47.4 and 57.9%, respectively. A control programme ofP. paradoxa was conducted using the techniques of pruning and worming besides spraying with bacterial insecticides at a rate of 200g/100 l.w. The performed mechanical and biological treatments together for one year gave 79.2–94.5% reduction of infestation, that reduction increased to 83.0–98.1% when these treatments were applied two years successively.     

Laboruntersuchungen zur Wirtshabitat-Wahl von Bracon brevicornis Wesm. (Hym., Braconidae), einem Parasitoiden der Raupen von Sesamia cretica Led. (Lep., Noctuidae) in Sorghum-Stengeln

Females of the parasitoid,Bracon brevicornis were more strongly attracted to “live” larvae ofSesamia cretica (themselves) than any other accessible materials (e. g. “stalk”, “frass”, “paralyzed larva” or control). They were also attracted to paralyzed larvae but only when live larvae were absent. On the other hand, males were more strongly attracted to “stalk” than to “live” larvae or any other available material. Apparently “stalk” exhibited an important cue that directed the parasitoid males.     

Investigations on side-effects of the mixed biocide GCSC-BtA on different predators of Plutella xylostella (L.) (Lep., Plutellidae) in southeastern China

The present paper deals with laboratory studies on side-effects of the mixed biocide GCSC-BtA on Plutella xylostella (L.) (Lep., Plutellidae) and its predators, e.?g. Amblyseius longispinosus (Evans) (Acari, Phytoseiidae), Erigonidium graminicola (Sundvall) (Araneae, Linyphiidae), Orius similis Zheng (Het., Anthocoridae) and Coccinella septempunctata L.(Col., Coccinellidae), in comparison to the commercial insecticides, e.?g. Abamectin, Tebufenozide, Dichlorvos, Cartap and Lambda-cyhalothrin. The results showed that GCSC-BtA was highly toxic to the 3^rd instar of P. xylostella with 91.18?% mortality, followed by Cartap with 84.38?%, Abamectin with 78.00?%, Tebufenozide with 75.57?%, Lambda-cyhalothrin with 63.75?% and Dichlorvos with 50.86?% mortality. On the other hand, GCSC-BtA was found to be comparatively less toxic to the predators, causing 31.11?%, 13.33?%, 11.54?% and 6.00?% mortalities in A. longispinosus, E. graminicola, O. similis and C. septempunctata, respectively. For comparison, the mortalities recorded for Abamectin, Tebufenozide, Dichlorvos, Cartap, Lambda-cyhalothrin were 72.94?%, 55.55?%, 70.00?%, 53.26?% and 98.85?% in A. longispinosus, 46.51?%, 55.10?%, 60.00?%, 46.00?% and 73.68?% in E. graminicola, 22.00?%, 16.00?%, 35.71?%, 26.78?% and 81.03?% in O. similis, 15.55?%, 19.64?%, 28.00?%, 16.66?% and 41.79?% in C. septempunctata, respectively. Cluster analysis was introduced to group the mortalities caused by the treatments into three toxicity groups with the distance of D?=?4.1. The 1^st group consisted of GCSC-BtA characterized with low toxicity to all the predators tested with 15.49?% mortality on average (highest 31.11?% and lowest 6.00?%). The 2^nd group consisted of Abamectin, Tebufenozide, Dichlorvos and Cartap with moderate toxicity to the predators with 39.96?% mortality on average. The 3^rd group included Lambda-cyhalothrin with high toxicity to the predators with 73.83?% mortality on average (highest 98.85?% and lowest 41.70?%). The susceptibility of the pest and its predators to GCSC-BtA and the insecticides is discussed. GCSC-BtA as a biological control agent is recommended for use in the integrated pests control programs in the vegetable fields.     

Application of some bacterial varieties ofBacillus thuringiensis and its bioproduct Delfin onSynanthedon myopaeformis Borkh. (Lep. Aegeriidae) in apple orchards

Field experiments were conducted using the biological agentBacillus thuringiensis to control the clearwing moth,Synanthedon myopaeformis (Lep. Aegeriidae) in apple orchards at Alexandria governorate during 1995, 1996 and 1997. Three bacterial varieties ofB. thuringiensis showed significant influence on the reduction of borer infestation. Four applications with the sporic concentration 12×10⁷ spores/ml of each ofB. th. var.kurstaki, B. th. var.alesti andB. th. var.thuringiensis induced 82.5, 51.1 and 42.1% reduction of infestation, respectively. Methods of application showed highly significant effect on infestation level. Sparying after scraping was the best method (80.0%, reduction) followed by painting after scraping (71.5%, reduction) then spraying alone (59.7%, reduction) or painting alone (43.0%, reduction). A control programme was carried out using three applications of the biomaterial, Delfin at the rate of 200 g/100 I.w. during mid-March, early June and mid-August resulted in 88.5–91.4% reduction of infestation.     

Laboratory evaluation and field application of bacterial and fungal insecticides on the citrus flower moth,Prays citri miller (Lep., hyponomeutidae) in lime orchards in Egypt

The efficacy of two commercial products of Bactospeine and Bio-fly onPrays citri of lime trees was studied under laboratory and field conditions throughout the two seasons of 1996 and 1997. Laboratory results indicated that the pathogenic effect of Bactospeine,Bacillus thuringiensis (Berliner) was higher than that of Bio-fly,Beauveria bassiana in spite of the latter was applied with higher doses. Bactospeine at the rate (2 cc/1 l.w.) effected on the larvae more than on the adults, that treatment reduced no. of eggs/female by 81.70% and decreased the larval infestation by 90.08%. Bio-fly at the highest concentration (4 cc/1 l.w.) reduced the infestation with the eggs, the larvae and the pupae by 65.83%, 68.45% and 72.55%, respectively. Advanced effects of bacterial and fungal treatments on the final reduction rates ofP. citri infestation were recorded. Field applications revealed that two sprays with Bactospeine or Bio-fly gave good control ofP. citri more than one spray. Bactospeine at the rate (2 cc/1 l.w.) and Biofly at the rate (4 cc/1 l.w.) reduced the infestation by (89.82–93.43%) and (76.32–78.83%), respectively. In all cases, higher doses of bioinsecticides produced potentiation effects of infestation reduction. It is recommended that two sprays of Bactospeine at a rate (2cc/1 l.w.) are adequate effective to reduce the population of P. citri in lime orchards during the main flowering period of trees without need of chemical insecticides. An erratum to this article is available at .