Maruca vitrata Fabricius (legume pod borer, LPB), the most serious economic pest of legume crops in the tropics, is primarily controlled by chemical pesticide application with serious consequences for the ecosystem and human health. In this study, various concentrations of three commercial biopesticides, NeemBaan®, Bactospeine® (Bacillusthuringiensis (Bt) subsp. kurstaki) and Florbac® (Btaizawai), were tested either in the field or laboratory or in both conditions. In the laboratory experiments, different concentrations of NeemBaan® exhibited significant effects on the mortality of all the tested larval instars and a mortality rate of over 80% was recorded at a dose of 3000 ppm. Bactospeine® was found to be more effective against M. vitrata than Florbac®. Bactospeine® applied at a lower dose of 500 ppm caused 100% mortality in the first-instar and second-instar larvae; however, at the same dose, Florbac® caused mortality of only 26.67% (first instar) and 20% (second instar). In the field experiments, a higher dose of NeemBaan® (6000 ppm) significantly reduced pod damage to approximately 20% in both the first and second cropping seasons. In conclusion, neem- and Bt-based biopesticide products have insecticidal potential to be used in an integrated pest management strategy for controlling M. vitrata in Thailand.

Chemical fertilizers for boosting crop production are becoming more expensive and scarce. Green amaranth (Amaranthus caudatus L.) is a fast growing and highly nutritious crop, but its common use in the diet of Nigerians is constrained by its high demand for nitrogen fertilizer. Thus, there is a need to find local fertilizer materials that are readily available to peasant farmers. A preliminary field study was conducted to evaluate urine and neem (Azadirachta indica L. juss) as alternative sources for mineral fertilizers in fortifying organic fertilizer (OF) made from cow dung and market waste compost, and OF fortified with urea and bone meal [organo-mineral fertilizer (OMF)], for yield and growth of green amaranth. Fifteen treatments, based on the percentages of N supplied, were NPK15-15-15, OMF, OF, urine, neem and ten treatments of 50, 60, 70, 80 or 90% OF supplemented with a total of 50, 40, 30, 20 and 10% urine or neem, respectively, to provide a total application rate of 100 kg N ha−1, with no fertilizer treatment as a control. Planting was done in two successions (main with fertilizer treatments and residual without further application). The fertilizer sources and levels had significant effects on plant height, number of leaves, stem girth, fresh weight and dry weight. The residual effects were also significant for plant height, number of leaves, total fresh and dry weights. Forty percent N urine amendment of the OF produced the highest total fresh amaranth biomass (269.3 g plot−1 main effect and 110.8 g plot−1 residual effect), which was significantly better than the values of (140 and 35.3 g plot−1, respectively) obtained with respect to OMF during main planting and NPK during residual planting. Results of our study reveal that 40% N urine fortification of OF was a viable substitute for synthetic fertilizers in production of amaranth, and that urine and neem cake can be alternatives to mineral fertilizer for crop production.

Seeds of neem (Azadirachta indica A. Juss.), a multipurpose tropical tree, have limited desiccation tolerance. Whether their intermediate storage behaviour might be caused by an elevated percentage of 4C nuclei in the embryo at maturity was investigated. Morphological development of neem seeds was monitored on selected trees in Ouagadougou, Burkina Faso. Developing seeds were tested for germinability, and cell cycle events were determined by using flow cytometry and analysing the level of β-tubulin. Germination could occur after 8 weeks of seed development, but normal seedlings resulted only after 10 weeks or more. The change in fruit colour from green to yellow began after approximately 12 weeks of seed development. Immature, 4-week-old embryos about 2 mm in length had 15% of cells in the G2 phase and 60% in the G1 phase of the cell cycle, as indicated by 4C and 2C nuclear DNA levels, respectively. During maturation, the proportion of G2 cells declined to 3% at full maturity and slightly further after drying, and the proportion of G1 cells increased to approximately 90%. A strong β-tubulin signal was observed in tips of young embryonic radicles and cotyledons, but a weak or non-detectable signal was found in 9-week-old ones and in those from green-mature and yellow fruits. Because DNA replication and β-tubulin level were almost negligible at seed maturity, as in orthodox tomato seeds, it is suggested that these factors are not involved in the intermediate storage behaviour of neem seeds.

The longevity of neem, Azadirachta indica, seeds from African Sahelian (Burkina Faso) and Asian (Sri Lanka) provenances was studied over two years of storage under different conditions of moisture and temperature. After drying to equilibrium moisture content (MC) at different relative humidities at 20°C, seeds were placed in open storage at 20°C or hermetically sealed in packets at temperatures ranging from −20 to +20°C. There was hardly any difference in storage behaviour between seed batches / lots, whatever their provenance. Seeds originating from mature yellow fruits lived longer than seeds from green or brown fruits. In all storage experiments with seeds having MCs ≥ 10%, viability was preserved best at 10−15°C, indicating that neem seed is chilling (and freezing) sensitive. There was no survival longer than 2 years under these conditions. At MCs of 4–8%, seeds were considerably more tolerant of low temperature storage and had 40–60% viability after 2 years at all temperatures tested (−20 to +20°C). However, the seeds were sensitive to imbibitional stress, which could be alleviated by imbibition at temperatures of 25–30°C or above. The difficult storage behaviour of neem seed seems to stem from: (1) the sensitivity to low temperatures at MCs ≥ 10%; (2) the extreme sensitivity to imbibitional stress after storage at ≤ 8% MC; (3) underestimation of the water activity due to the high oil content of the neem seeds, causing unexpected metabolic stress in the higher MC and temperature range.

Neem products are often perceived as harmless to natural enemies, pollinators and other non-target organisms. For this reason, several integrated pest management (IPM) programmes have adopted neem as one of the prime components. This study revealed toxic effects of neem on soil-inhabiting and aerial natural enemies in chickpea to an extent of 41 and 29% population reduction, respectively, compared with 63 and 51% when using a conventional insecticide (endosulfan). Neem also affected the parasitization of Helicoverpa armigera (Hübner) larvae by Campoletis chlorideae Uchida up to 20%. The natural enemy population started building up from the vegetative phase and reached their peak during the reproductive phase, and there was a gradual decline from pod formation to pre-harvest phases of the crop. Adapting the currently used IPM system in chickpea using neem during the vegetative phase, followed by an application of Helicoverpa nuclear polyhedrosis virus (HNPV) at flowering and need-based application(s) of chitin inhibitors like novaluron or flufenoxuron instead of endosulfan during pod formation would strongly augment natural enemy populations. This paper discusses the relative toxicity of neem and other IPM components on soil-inhabiting and aerial natural enemies in the chickpea ecosystem.

The efficacy of neem (1500 ppm azadirachtin (AI)), Delfin®WG™, a biological insecticide based on selected strain of Bacillus thuringiensis Berliner (Bt) subspecies kurstaki, and Cry1Ac protein, either individually or in combination, were examined against first to fourth instar Helicoverpa armigera (Hübner) larvae. Using an oral administration method, various growth inhibitory concentrations (EC) and lethal concentrations (LC) were determined for each bioagent. Combinations of sublethal concentrations of Bt spray formulation with azadirachtin at EC50 or EC95 levels not only enhanced the toxicity, but also reduced the duration of action when used in a mixture. The LC20 and LC50 values for Cry1Ac toxin were 0.06 and 0.22 μg ml−1, respectively. Bt–azadirachtin combinations of LC50+EC20 and LC50+EC50 result in 100% mortality. The mortality also was significant in LC20+EC20 and LC20+EC50 mixtures. These studies imply that the combined action is not synergistic but complimentary, with azadirachtin particularly facilitating the action of Bt. The Bt spray–azadirachtin combination is more economical than combinations that involve isolating the toxic protein, as the Bt spray formulations can be combined in a spray mixture with neem. These combinations may be useful for controlling bollworm populations that have acquired resistance to Bt as they may not survive the effect of mixture. Azadirachtin may be useful as a means of reducing the endotoxin concentrations in a mixture, to promote increased economic savings and further reduce the probability of resistance development to either insect control agent.

Cocoa (Theobroma cacao L.) is an important foreign exchange earner for Ghana. However, production is constrained by a high incidence of pests and diseases. Based on farmers' needs, this study focused on the control of capsids, mainly Sahlbergella singularis Haglund and Distantiella theobroma (Distant) (both Hemiptera: Miridae). Annual crop loss caused by capsids is estimated at 25–30%. To control capsids, formal research recommends application of synthetic insecticides four times between August and December. However, farmers hardly adopt this recommendation, which they consider unsuitable for their conditions and context. Three alternative control methods were tested with farmers: mass trapping, using sex pheromones; applying crude aqueous neem Azadirachta indica A. Juss. (Meliaceae) seed extract (ANSE) and using the predatory ant Oecophylla longinoda Latreille (Hymenoptera: Formicidae) as a biological control agent. Contrary to most previous reports, studies on temporal distribution of cocoa capsids indicated that the population peaked in March. ANSE was effective against capsids and other cocoa insect pests and did not affect the predatory ant. When O. longinoda occurred in high numbers, capsid incidence was low. Shade did not influence ant or capsid abundance significantly. ANSE caused 100% mortality of capsids in cage and 79–88% in field experiments. The sex pheromone was as effective as ANSE or ants in suppressing capsids. All the three methods were effective and compatible; hence, they can be used in an integrated pest management strategy for cocoa, including organic production in Ghana.

Neem (Azadirachta indica A. Juss.) has been demonstrated to reduce insect populations in stored products through its toxic and growth-disrupting and other effects on the pests. Grain movement and percussion also help to kill pests in grain. The combination of neem and grain movement on population growth and development of four insect pests is reported in this study. Dried whole neem leaves, neem leaf powder and neem seed kernel oil were combined individually with dried beans and rice in separate experiments, and subjected to varying degrees of gentle grain tumbling. The results showed that the combined treatments were more effective in reducing populations and disturbing growth and development of Acanthoscelides obtectus (Say) (Bruchidae), Sitophilusoryzae (Linnaeus) (Curculionidae), Oryzaephilus surinamensis (Linnaeus) (Silvanidae) and Cryptolestes ferrugineus (Stephens) (Cucujidae) compared to the untreated control or the neem or tumbling treatments alone. This study demonstrates the potential of a simple, effective and cheap method of protecting stored seed or food grain in small-scale storage for resource-poor farmers who do not have access to sophisticated control methods, entoleters or other mechanical devices for grain protection.

The effects of four different neem formulations (Neemros®, Neemroc EC®, Neemroc Combi and Saroneem) and a combination of Neemros® with a synthetic acaricide (Mitac®) on the twospotted spider mite (Tetranychus urticae Koch) were compared with Mitac® on tomato (Lycopersicon esculentum Mill.) leaf discs in the laboratory, The following LC50 were determined: Neemroc EC® 12.9 ml/1, Saroneem 5.8 ml/1, Neemroc Combi 1.0 ml/1 and Mitac® + Neemros® 1 ml/1 + 17.6 g/1. No LC50 was determined for Neemros® since the highest mortality observed was 11.4 %. The combination of Mitac® and Neemros® resulted in the highest mortality after 24 hours (83.3 %), followed by Neemroc EC® (78.3 %), Saroneem (53.4 %), Mitac® (50.8 %), Neemroc Combi (38.9 %), the control (4.5 %) and Neemros® (0.0 %). All neem formulations also caused repellence and oviposition deterrence in T. urticae.

The efficacy of neem kernel cake powder water extract (NKCP-WE) and Dipel 2x (Bacillus thuringiensis var. kurstaki) in controlling the diamondback moth (DBM), Plutella xylostella Linn. (Lepidoptera: Yponomeutidae), on cabbage was evaluated in screenhouse experiments. All concentrations of NKCP-WE tested were larvicidal and plants treated with 25 and 50 g/l NKCP-WE retained larvicidal activity for up to 2 weeks after application. The efficacy of 25 and 50 g/1 NKCP-WE and 0.5 g/1 Dipel 2x was compared by observing DBM development on the treated plants and yields of those plants. Dipel 2x-treated plants had less DBM larval infestation than the neem-treated plants but the latter treatment gave better yield. The implications of these observations are discussed.

Aqueous neem seed kernels extracts (NSKE) were used to treat flea-infested goats in Morogoro, Tanzania to determine their efficacy for flea control. Mean population densities of the insects were significantly lower in the treated goats compared to their untreated counterparts (P < 0.05). It was concluded that NSKE has potential in controlling livestock fleas, but further studies are needed to determine the active principals against fleas and their mode of action.

The effectiveness of aqueous neem leaf and seed extracts for the control of the diamondback moth (DBM), Plutella xylostella (Linnaeus) (Lepidoptera: Plutellidae) on cabbage was evaluated in field tests at Chokwe, Mozambique and compared with parallel dimethoate + cypermethrin treatments. All the neem treatments recorded significantly higher yield of marketable heads of cabbage and significantly better control of diamondback moth than the commonly used mixture of pyrethroids or the untreated control. The neem seed extracts provided the best control of DBM. The possibility of using neem extracts as part of an integrated pest management system for DBM control in smallholder farms is discussed.

The influence of post-treatment temperature on the insecticidal activity of Azadirachta indica (A. Juss) seed extract against the desert locust, Schistocerca gregaria (Forskål) is reported. In tests on adults, the toxicity of crude A. indica seed extract increased by about 10-fold when the post-treatment temperature was raised from 22°C to 40°C. This temperature-dependent toxicity was observed in insects treated either topically or via injection. This phenomenon could partly explain the wide variability in efficacy of neem extracts reported by different investigators.

The oviposition-deterrent and toxic effects of seven plant species with known biological effects were tested against the Adzuki bean beetle, Callosobruchus chinensis L. (Goleoptera: Bruchidae) on stored faba bean seeds for two years at Holetta Research Centre, Ethiopia. Oils of Azadirachta indica, Milletiaie ferrnginea and Chrysanthemum cineraraefolium were the most effective in partially or completely preventing egg laying, and no bruchids emerged from the few eggs laid. The Phytolacca dodecandra, Hagenia abyssinica and Schinus molle treatments had no significant effect on the bruchids and most of the eggs laid developed into adults. Eucalyptus globulus seed powder treatment caused the death of only emerging adult beetles.

The effects of neem seed kernel extract (NSKE), neem oil (NO) and nucleopolyhedrovirus (NPV) of the Spodoptera litura Fabricius (Lepidoptera: Noctuidae) on the mortality, feeding and development of S. litura were evaluated in the laboratory. Dose-dependent mortality was evident after NPV treatment, which also depended on larval age at treatment. Upon combining NPV with neem products, the percentage mortality was enhanced threefold even at reduced concentrations. The NSKE and NO significantly inhibited the growth and development of S. litura, and extended the duration of its larval and pupal stages. Oviposition period, adult longevity and fecundity were significantly reduced following treatment with neem products and with neem + NPV treatment. The efficiencies of conversion of ingested food (ECI) and digested food (ECD) were also significantly decreased by treatment with NSKE, NO and NPV, either alone or in combination.

Gas-liquid chromatography was used to analyse the saponifiable and unsaponifiable fractions of petroleum ether (PE) extracts of neem fruits and leaves. Both fractions, as well as a crude PE extract, were assayed for biological activity against third instar cotton leafworm, Spodoptera littoralis.

In neem fruits, eighty-eight percent (88%) of the saponifiable matter consisted of saturated fatty acids, while 12% was composed of unsaturated fatty acids. In the neem leaves, the corresponding proportions were 62 and 38%, respectively. Unsaponifiable matter of both fruits and leaves contained varying amounts of hydrocarbons and sterols. All the tested extracts demonstrated significant larvicidal effects against leafworm larvae. They also prolonged larval duration, caused malformations of the resulting pupae and significant adverse effects on the fecundity of resulting adults.

Azadirachtin, the principal active ingredient of neem seed and aqueous neem seed extracts (ANSE) reduced food intake and utilisation efficiency in the penultimate instar level of the African armyworm (Spodoptera exempta) when applied either topically or mixed with the diet of the insect. These observations reflect interference of neem with centres in the insect that regulate feeding and metabolism. The decreased food utilisation efficiency in treated insects indicated higher metabolic costs as they had to direct some energy into dealing with neem deposits in their bodies rather than biomass production.

Fourth instar larvae of laboratory-reared, Ctenocephalides felts and Xenopsylla. brasiliensis were exposed to 50% neem seed kernel extract (NSKE) for periods varying from 30 min to 24 hr. Mortality of larvae was observed from exposure periods of 2 hr and above in both species. At 24 hr exposure, 95.3% and 94.7% of C.felis and X. brasiliensis respectively were killed. LT50s were approximately 6 and 10.5 hr for C.felis and X. brasiliensis respectively. It was generally concluded that neem seed kernel extract was potentially larvicidal against the two flea species and that it could be effectively used for controlling the insects by properly dusting the latter's breeding sites with appropriate concentrations of the extract.

Termites are important agricultural pests in the semi-arid tropics. Conventional methods of control have relied on persistent organochloride insecticides with accompanying health and environmental problems. In contrast, cultural control methods provide untested, but environmentally sound options to farmers. This study reports results from three experiments on the use of mulches to reduce Microtermes obesi and Odontotermes spp. damage with relevance to groundnut production in India.

Termites scarification of groundnut was 80–90% lower for pods dried in neem cake or Ipomoea fistulosa mulches than for pods dried directly on the soil. Similarly, subterranean attack by termites on bamboo baits was 20–40% lower in mulched plots than in controls. However, mulches were ineffective in protecting bullock manure from removal by termites.

Successful use of mulches in termite control may be related to food source concentration. Termite location of concentrated food sources, such as bullock manure, was followed by recruitment of workers and construction of protected runways. In contrast, termites foraging on limited food sources, such as groundnut pods, did not construct runways and had greater exposure to mulches.

Three neem products—an emulsifiable concentrate of neem oil (NOEC), neem kernel water extract (NKWE) and neem leaf water extract (NLWE)—were applied on field cassava for protection against damage by the grasshopper, Zonocerus variegatus (L.). Three conventional insecticides viz. lindane 0.3%, cypermethrin 0.006% and monocrotophos 0.24% were also compared. All the neem products protected cassava for varying periods. Efficacies of NOEC and NKWE were superior to insecticides. From the results, neem products recommended to check the grasshopper damage were as follows: NOEC 0.5–2% to be applied every 8 days, NOEC 3–4% to be applied every 10 days, NKWE 7–10% to be applied every 12 days, NLWE 50% to be applied every 6 days.