Feeding behavior ofCryptolaemus montrouzieri on mealybugs parasitized byAnagyrus pseudococci

The citrus mealybugPlanococcus citri (Risso) and the vine mealybugPlanococcus ficus (Signoret) (Hemiptera: Pseudococcidae) are two worldwide polyphagous pests of citrus, vineyards and ornamental plants in greenhouses. Biological control of these pests may rely on the combined release of parasites and predators, which can be affected by intraguild predation (IGP). This study investigated the feeding behavior of different stages ofCryptolaemus montrouzieri Mulsant (Coleoptera: Coccinellidae) on mealybugs parasitized byAnagyrus pseudococci (Girault) (Hymenoptera: Encyrtidae) 2, 4, 6, 8 and 10 days. The study was conducted in a climate-controlled room at 28±1° C, 16L:8D, and 65±10% r.h. The highest consumption values for all stages ofC. montrouzieri occurred with 2- and 4-day parasitized mealybugs, whereas the predator did not feed on either species of mealybug parasitized for longer periods, due to the onset of mummification. http://www.phytoparasitica.org posting August 4, 2008.     

Efficacy of neem seed derivatives against nematodes affecting banana

Soil applications of powdered neem seed or neem cake at 100 g/plant at planting and, subsequently, at 3-month intervals, reduced the populations ofPratylenchus goodeyi Sher & Allen andMeloidogyne spp. on par with Furadan 5G (carbofuran) applied at 40 g/plant at planting and then at 6-month intervals to banana plants grown in 100-/ containers with controlled levels of banana nematode infestations. Eight months after planting, banana plants treated with powdered neem cake, seed or kernel or with neem oil had 4 to 95 times fewer parasitic nematodes than the untreated control. However, only neem cake powder or neem seed powder applied to unpared banana plants kept the nematode population below the economic threshold.     

Neem seed extract spray applications as low-cost inputs for management of the flower thrips in the cowpea crop

In field trials conducted at the Experiment Station and in a farmer’s field at Mbita near the shores of Lake Victoria, Kenya, applications of 2% or 3% neem seed extract (NSE) @ 200 l/ha with a knapsack sprayer at 38, 47 and 51 days after emergence (DE) of the cowpea crop or 5%, 10% or 20% NSE sprayed @ 10 l/ha with an ultra-low-volume applicator at 31, 39 and 49 DE often significantly reduced the number of larvae of the flower thrips,Megalumthrips sjostedti (Trybom), in cowpea flowers recorded 2 days after each treatment. Also fewer adults occurred in flowers at 51 DE in plots sprayed with 5%, 10% or 20% NSE. Cowpea grain yield was significantly higher in plots sprayed with 20% NSE than in untreated control plots and was comparable to the grain yield obtained in plots sprayed thrice with cypermethrin. Because of the low cost of NSE treatment, the net gain was often more when the crop was sprayed with NSE than with cypermethin. Also, grain quality was superior in neem-treated plots than in untreated or cypermethrin-treated plots.     

Effects of neem (Azadirachta indica) extracts onLeptocorisa chinensis under choice and no-choice conditions

Two extracts from neem (Azadirachta indica A. Juss. (Meliaceae)) seeds, azadirachtin and oil, and a mixture of neem oil and abamectin, were tested on second-instar nymphs of the rice bugLeptocorisa chinensis (Dallas) (Hemiptera: Alydidae). To clarify the effect of spraying coverage on bioefficacy of test materials, experiments were conducted under choice and no-choice conditions in field cages. In a choice test, treatment with the mixture of neem oil and abamectin was most effective in reducing the survival ofL. chinensis, followed by azadirachtin at 60 ppm, 30 ppm and 3% neem oil, whereas all treatments except neem oil caused 100% mortality within 3 weeks in a no-choice test. When second-instar nymphs had choices of treated and untreated plants within a treatment, no differences in yield and sum of dead and stained grains were found between those two choices, indicating that nymphs neither caused significant reduction in yield nor reduced the quality of untreated plants. Regardless of treatment, the difference in overall yield between treated and untreated plants under choice conditions was not statistically significant (P>0.05). Our results indicate that neem-based formulations, used alone or in combination with abamectin, have the potential to be integrated into the existing programs to control the rice bug. http://www.phytoparasitica.org posting Aug. 28, 2005.     

The antifeedant effect of neem seed kernel extract and azadirachtin on nymphs ofEyprepocnemis plorans

Acridids belonging to different species and families exhibit large differences in their response to neem components. In this context the antifeedant effect of a methanolic neem seed kernel extract (NSKE) and of azadirachtin (AZA) on fourth-instar nymphs of the acrididEyprepocnemis plorans Charpentier (Saltatoria:Acrididae) was investigated. Nymphs were offered either saccharose-impregnated filter paper disks or leaves of broad beans, treated with neem components. The amount of substrate consumed was determined by weighing the filter paper or by measuring the leaf area. On filter paper both NSKE and AZA were highly active down to the 10⁻⁴% treatment. In the leaf treatment, however, AZA was definitely more active than NSKE, with 100% deterrence at 10⁻⁴% and 10⁻²%, respectively. The methanolic NSKE was somewhat more active than the commercial preparation ‘Neemark’.     

Effect of Margosan-O on the development ofEarias insulana

The effect of Margosan-O, a formulation of a natural insecticide obtained from the neem tree (Azadirachta indica A. Juss), on the development of and the penetration rate of larvae of the spiny bollworm,Earias insulana (Boisd.), into cotton bolls was investigated by (i) incorporating Margosan-O into a semisynthetic diet and recording mortality until the adult stage; and (ii) spraying leaves and bolls with, or standing cotton seedlings or twigs of cotton with one boll per twig in aqueous dilutions of Margosan-O in an attempt to protect leaves or cotton bolls from feeding or penetration, respectively, by the larvae. Margosan-O was found to be effective when incorporated into the semisynthetic diet, even at low concentrations, especially when it was offered throughout the larval life span. Survival rate and average weight of the larvae were much lower on leaves treated with 0.5% or 0.2% Margosan-O, or exposed to its systemic effect at 0.5% or 0.25%, than on control leaves. Larval penetration into Margosan-O-sprayed bolls at concentrations of 0.01– 0.5% wasca 30–45% of that into control bolls. Margosan-O was active also as systemic treatment: onlyca 35% of the larvae penetrated the 0.25%-treated bolls compared with the untreated ones.     

Age,body size and sex-related feeding response of the predatory coccinellid Cryptolaemus montrouzieri Mulsant

The objective of this study was to determine the effect of age, body size and sex on feeding rate of the predatory coccinellid Cryptolaemus montrouzieri Mulsant (Coleoptera: Coccinellidae). The body size of the adult C. montrouzieri did not influence the feeding rate in either sex and the large body size was more common in both sexes. A significant increase in feeding (4.64 mealybugs/ day) and excretion (47.91 excreta deposits/ day) was observed in females compared with males (2.47 mealybgs/ day and 25.78 excreta deposits/ day, respectively) under mated conditions. The feeding rate throughout adulthood showed an inverse trend with age in both sexes and the curvilinear relationship explained much of the variability in the feeding response in relation to age. The feeding differences in relation to age, body size as well as sex of adult C. montrouzieri are discussed in detail.     

The potential of combining <Emphasis Type="Italic">Pasteuria penetrans</Emphasis> and neem (<Emphasis Type="Italic">Azadirachta indica</Emphasis>) formulations as a management system for root-knot nematodes on tomato

Initial applications of 10⁴ spores g⁻¹ of Pasteuria penetrans, and dried neem cake and leaves at 3 and 2% w:w, respectively, were applied to soil in pots. Juveniles of Meloidogyne javanica were added immediately to the pots (500, 5,000 or 10,000) before planting 6-week-old tomato seedlings. The tomatoes were sampled after 64 days; subsequently a second crop was grown for 59 days and a third crop for 67 days without further applications of P. penetrans and neem. There was significantly less root-galling in the P. penetrans combined with neem cake treatment at the end of the third crop and this treatment also had the greatest effect on the growth of the tomato plants. At the end of the third crop, 30% of the females were infected with P. penetrans in those treatments where spores had been applied at the start of the experiment. The effects of neem leaves and neem cake on the nematode population did not persist through the crop sequences but the potential for combining the amendments with a biological control agent such as P. penetrans is worthy of further evaluation.     

Effect of some biorational insecticides on Spodoptera eridania in organic cabbage

BACKGROUND: To reduce pest attack, several biorational products are allowed for use on organic vegetables in Brazil. This study investigated eight biorational products applied singly or in combination against Spodoptera eridania Cramer in field plots of cabbage intercropped with coriander. The treatments were applied once a week over a 5 week period, beginning 34 days after transplanting. The evaluations consisted of counting the larvae of S. eridania on the day before and 7 and 21 days after spraying. The damage to leaves and cabbage head, the commercial weight of head and the percentage of head losses were evaluated.RESULTS: Leaf injury in plots treated with Beauveria bassiana and neem oil (Dalneem) yielded scores of 1.3 and 2.5 (scale ranging from 0 to 4) respectively, in comparison with a score of 3.6 from untreated plots. Head weight losses were 6.1, 5.3 and 4.9% with an aqueous extract of neem leaves, neem oil and B. bassiana respectively, compared with 24.6% lost from untreated plots.CONCLUSION: Dalneem, B. bassiana and the extract of neem leaves at 20% exhibited the best performance for control of S. eridania.     

Biological activity of neem against the red pumpkin beetle,Aulacophora Foveicollis

The biological activity of neem on the red pumpkin beetle,Aulacophora foveicollis Lucas, was studied. The effective concentration for 50% antifeedant activity was 0.01% methanolic neem seed kernel extract (NSKE) and 0.4% neem oil, using leaves of muskmelon as feeding substrate. No-choice feeding of adults for a period of 11 days on leaves of muskmelon treated with 0.5-2.0% NSKE led to nearly 50% mortality within 4-7 days, whereas there was no mortality of adults fed on as high as 2% neem oil. The antifeedant activity of NSKE was found to vary with curcurbitaceous hosts. Neem oil as a residual film had an LC₅₀ of 0.7%. Unlike most chemical insecticides, 1% aqueous NSKE was not phytotoxic to the 5-day-old cotyledon stage and to 15- and 35-day-old crop stages of muskmelon, whereas 1% neem oil was toxic to the 5-day-old cotyledon stage and 15-day-old crop of muskmelon, but not to the 35-day-old crop.     

Effect of Margosan-O on the development of the leafhopperasymmetrasca decedens

The effect of Margosan-O, a formulation of a natural insecticide obtained from the neem (Azadirachta indica A. Juss) tree, on the development of the leafhopperAsymmetrasca decedens (Paoli), was investigated by testing insect performance (i) on cotyledons ofGossypium hirsutum cotton seedlings treated with different concentrations; (ii) on cotton seedlings stood with their petioles in different aqueous dilutions of Margosan-O and recording mortality until the adult stage; and (iii) determining the repellent effect on adults by recording their location on treatedvs untreated cotyledons in choice and no-choice situations. In foliar and in systemic treatments with 2% Margosan-O, practically none of the leafhoppers reached the adult stage. As the concentrations were lowered there was a gradual rise in the percentage of adults emerging; on untreated cotyledons 60-80% of the adults emerged. Feeding was zero or very low at high Margosan-O concentrations. Adult leafhoppers settled in significantly higher numbers on untreated than on treated cotyledons in both choice and no-choice experiments.     

Neem (Azadirachta indica) seed kernel extracts and azadirachtin as oviposition deterrents against the melon fly (Bactrocera cucurbitae) and the oriental fruit fly (Bactrocera dorsalis)

Neem(Azadirachta indica A. Juss.) seed kernel (NSK) extracts,viz., NSK aqueous suspension (NSKS), ethanolic extract of NSK (EtOH. NSK), hexane extract of NSK (neem oil), ethanolic extract of the hexane extract (EtOH. oil) and acetone extract of deoiled NSK powder (Acet. DNSKP) at 1.25-20% concentrations, and pure azadirachtin at 1.25-10 ppm, were evaluated as oviposition deterrents toBactrocera cucurbitae (Coq.) andB. dorsalis Hendel. NSKS at ≥5% under choice test conditions, and at all concentrations (≥1.25%) in no-choice tests significantly deterred oviposition in both species. Similarly, EtOH. NSK was significantly active at all the concentrations tested for both species in choice and no-choice tests. However, with neem oil and EtOH. oil sensitivities of the two species differed considerably. Both extracts deterred oviposition byB. cucurbitae at all the concentrations tested under both choice and no-choice test conditions. On the other hand, withB. dorsalis, neem oil was significantly deterrent only at 20% in both test regimes and at 5% and 20% for EtOH. oil under choice and no-choice test conditions, respectively. Acet. DNSKP significantly deterred oviposition by both species at all concentrations tested. Azadirachtin failed to deter oviposition in either species.     

Effect of biopesticides applied separately or together on nutritional indices of the rice leaffolderCnaphalocrocis medinalis

Laboratory assays were done to evaluate the effect of neem seed kernel extract (Azadirachta indica A. Juss),Vitex negundo L. (Lamiales: Verbenaceae) leaf extract, andBacillus thuringiensis (Berliner), applied separately or together, on nutritional indices of the rice leaffolderCnaphalocrocis medinalis (Guenée) (Lepidoptera: Pyralidae). All three biopesticides suppressed feeding and larval growth and low concentrations affected the larval performance. The combined effect of the three biopesticides resulted in a considerable decrease in nutritional indices, indicating strong deterrence. Dose response relationships were established with respect to frass production and larval growth. The efficiency of conversion of ingested and digested food was considerably reduced.     

Effects of a formulation of neem extract on six species of cockroaches (Orthoptera: Blaberidae,Blattidae and Blattellidae)

Margosine-0®, a commercial preparation of neem seed extract, was tested for its effects as a toxicant, growth inhibitor, or repellent against six species of cockroaches —Blatta orientalis L.,Blattella germanica (L.),Byrsotria fumigata Guérin-Méneville,Gromphadorhina portentosa (Schaum),Periplaneta americana (L.), andSupella longipalpa (F.) (Orthoptera: Blaberidae, Blattidae, and Blattel-lidae). Last-instar nymphs of these species fed Lab-Chow® pellets impregnated with neem extract at a rate of 0.5 ml/pellet showed increased mortality and retarded development. All lst-instar nymphs ofB, orientalis, B. germanica andS. longipalpa died after consuming treated Lab-Chow pellets. Topical application of 2 μl of Margosine-0 to the abdomens of last-instarB. orientalis nymphs, as well as injection of 0.5 μl, resulted in reduction of growth and increased mortality. Placing lst-instarB. orientalis nymphs on a surface treated with the neem extract had no notable effect. In a choice test,P. americana adults immediately preferred the pellets treated with 0.5 ml of neem extract, but pint cardboard cartons treated with 1.5 ml extract repelled them.     

The insecticidal and acaricidal actions of compounds fromAzadirachta indica (A. Juss.) and their use in tropical pest management

The pest control potential demonstrated by various extracts and compounds isolated from the kernels and leaves of the neem plant (Azadirachta indica) A. Juss. (Meliaceae) seem to be of tremendous importance for agriculture in developing countries. Laboratory and field trial data have revealed that neem extracts are toxic to over 400 species of insect pests some of which have developed resistance to conventional pesticides, e.g. sweet potato whitefly (Bemisia tabaci Genn. Diptera: Aleyrodidae), the diamond back moth (Plutella xylostella L. Lepidoptera: Plutellidae) and cattle ticks (Amblyomma cajennense F. Acarina: Ixodidae andBoophilus microplus Canestrini. Acarina: Ixodidae). The compounds isolated from the neem plant manifest their effects on the test organisms in many ways, e.g. as antifeedants, growth regulators, repellents, toxicants and chemosterilants. This review strives to assess critically the pest control potential of neem extracts and compounds for their use in the tropics. This assessment is based on the information available on the wide range of pests against which neem extracts and compounds have proven to be toxic, toxicity to non-target organisms, e.g. parasitoids, pollinators, mammals and fish, formulations, stability and phytotoxicity.     

Powdered neem seed and cake for management of the banana weevil,cosmopolites sordidus, and parasitic nematodes

Field trials were conducted in Kenya with ‘Nakyetengu’, an East African highland banana cultivar (AAA-EA), highly susceptible to banana pests. Regardless of soil fertility levels, incorporation around the plant base of powdered neem(Azadirachta indica A. Juss.) seed or cake at 60-100 g/mat at 4-month intervals, gave better control of the banana weevil,Cosmopolites sordidus (Germar), and of parasitic nematodes, than that achieved with soil application of Furadan 5G (carbofuran) at 60 g/mat at 6-month intervals. Compared with untreated control, fruit yield in most of the neem treatments was significantly higher, particularly during the second cycle of crop production. Neem application conferred a net economic gain, whereas Furadan application proved uneconomical. Application of powdered neem seed or cake at higher rates (200–400 g/mat) at 6-month intervals caused phytotoxicity, resulting in drying up of banana plants before fruiting, or in ‘chokethroat’,i.e., inflorescence emergence failure.     

Feeding potential of <Emphasis Type="Italic">Cryptolaemus montrouzieri</Emphasis> against the mealybug <Emphasis Type="Italic">Phenacoccus solenopsis</Emphasis>

Phenacoccus solenopsis Tinsley (Hemiptera: Pseudococcidae) is an exotic species native to the USA, damaging cotton and other plant families. The feeding potential of different development stages of Cryptolaemus montrouzieri Mulsant, a biological control agent against mealybugs, was investigated on different development stages of P. solenopsis. Fourth instar grubs and adults of C. montrouzieri were the most voracious feeders on different instars of mealybug. The number of 1^st instar nymphs of mealybug consumed by 1^st, 2^nd, 3^rd and 4^th instar larvae and adult beetles of C. montrouzieri was 15.56, 41.01, 125.38, 162.69 and 1613.81, respectively. The respective numbers of 2^nd and 3^rd instar nymphs of mealybug consumed were 11.15 and 1.80, 26.35 and 6.36, 73.66 and 13.32, 76.04 and 21.16, 787.95 and 114.66. The corresponding figures for adult female mealybugs were 0.94, 3.23, 8.47, 12.71 and 73.40, respectively. The results indicate that C. montrouzieri has the potential to be exploited as a biocontrol agent in North India; inoculative releases of 4^th instar larvae and adults may provide instant control of P. solenopsis. Field experiments should be conducted to determine the efficiency of the ladybird on this mealybug.     

Soil application of imidacloprid and related SAR-inducing compounds produces effective and persistent control of citrus canker

Soil application of the systemic insecticide imidacloprid (Admire®, Bayer Crop Science) produced season-long control of citrus canker caused by Xanthomonas citri sbsp. citri. Imidacloprid is a neo-nicotinoid that breaks down in planta into 6-chloronicotinic acid, a compound closely related to the systemic acquired resistance (SAR) inducer isonicotinic acid. Potted Swingle citrumelo seedlings (Citrus paradisi × Poncirus trifoliata) were treated with imidacloprid and the SAR inducers, isonicotinic acid, and acibenzolar-s-methyl as soil drenches or with acibenzolar-s-methyl as a foliar spray 1week prior to inoculation of immature leaves with X. citri sbsp. citri. Seedlings were re-inoculated four times over a 24-week period. SAR induction was confirmed by expression of the PR-2 gene (β-1,3 glucanase). Soil drenches of imidacloprid, isonicotinic acid, and acibenzolar-s-methyl induced a high and persistent up-regulation of PR-2 gene expression and reduced the number of canker lesions for up to 24 weeks compared to 4 weeks for foliar acibenzolar-s-methyl. Soil applied inducers of SAR reduced canker lesions up to 70% compared with the untreated inoculated plants. Lesions on leaves were small, necrotic, and flat compared to pustular lesions on inoculated untreated plants. Populations of X. citri sbsp. citri per leaf were reduced 1–3 log units in soil-treated plants compared to inoculated untreated plants.     

The toxicity and physiological effect of neem limonoids on Cnaphalocrocis medinalis (Guenée) the rice leaffolder

The effect of neem (Azadirachta indica) limonoids azadirachtin, salannin, deacetylgedunin, gedunin, 17-hydroxyazadiradione, and deaceytlnimbin on gut enzyme activity of the rice leaffolder larvae was investigated. When fed a diet of rice leaves treated with limonoids in bioassays, gut tissue enzymes—acid phosphatases (ACP), alkaline phosphatases (ALP), and adenosine triphosphatases (ATPase) activities of rice leaffolder (Cnaphalocrocis medinalis) larvae are affected. Azadirachtin was most potent in all experiments. Larvae that were chronically exposed to limonoids showed a reduction in weight (59-89%) and exhibited a significant reduction in ACP, ALP, and ATPase activities. These results indicate neem limonoids affects gut enzyme activities. These effects are most pronounced in early instars.     

Effects of a neem-based insecticide on different immature life stages of the leafminerLiriomyza sativae on tomato

The effects of the commercially available neem insecticide NeemAzal-T/S® (neem) (1% azadirachtin) onLiriomyza sativae (Diptera: Agromyzidae) were studied on tomato in Bangkok, Thailand. Neem emulsions were sprayed on the aerial plant parts at five concentrations (from 0.001% to 0.010% a.i.); different aged residues (0, 1, 3, 5, and 7 days) were tested, in both controlled environment rooms and in greenhouses. Irrespective of the residual age of the application, no significant effects on oviposition or egg hatch were detected. However, neem drastically increased larval mortality at the higher concentrations tested. The L1 and L2 larvae were most susceptible. Irrespective of concentration, larval mortality or inhibition of adult eclosion decreased much faster in greenhouses than in controlled environments with artificial light. Nevertheless, our results suggest that neem has potential to controlL. sativae in netted greenhouses.