Integration of Calneem® oil and parasitoids to control <Emphasis Type="BoldItalic">Cadra cautella</Emphasis> and <Emphasis Type="BoldItalic">Corcyra cephalonica</Emphasis> in stored grain cereals

The compatibility and protectant potential of Calneem® oil derived from the neem tree Azadirachta indica and two parasitoids, Habrobracon hebetor and Venturia canescens, for the control of the rice moth Corcyra cephalonica (Stainton) (Lepidoptera: Pyralidae) and the tropical warehouse moth Cadra cautella Walker (Lepidoptera: Pyralidae) in stored rice and wheat, were evaluated in the laboratory. Calneem® oil (= neem oil) is a biopesticide produced, registered and marketed in Ghana by AQUA AGRIC Community Projects (AACP/Caldor Ghana Ltd., Tema). It contains 0.3% azadirachtin as its major active ingredient. The oil was emulsified with water using 0.07% soap. Fourth instar moth larvae were held in grain treated with neem oil only, grain treated with one of the parasitoids only, grain treated with a combination of neem and one of the parasitoids, and a control with untreated grain. Neem oil was applied at concentrations from 5,000 to 30,000 ppm. All samples were kept in growth cabinets maintained at 25°C and 65–70% r.h. Adult emergence was recorded after 4 weeks. Parasitoid or neem treatments alone reduced the emergence of C. cephalonica and C. cautella. In general, parasitoid releases were as effective as a combination of neem oil and parasitoids. At the lowest dose, 5,000 ppm, the combination of neem and parasitoid was more effective than the neem alone. The number of adults of H. hebetor and V. canescens that emerged in rice containing either parasitoids alone or in combination with neem oil was similar. This indicates minimal or no adverse effect of neem oil on the two parasitoids. It is thus possible to incorporate neem oil in a well-designed pest management program with parasitoids.     

Insecticidal efficacy of botanical food by-products against selected stored-grain beetles by the combined action with modified diatomaceous earth

Journal of Plant Diseases and Protection - Farmers in Africa in general have repeatedly prioritized the urgent need for improved methods of storage pest control. Laboratory studies were evaluated...     

Preliminary inventory of hymenopteran parasitoids associated with fruit-infesting flies (Diptera: Tephritidae) in Northern Ghana

Baseline studies were conducted to determine the parasitoids associated with fruit flies in the northern savanna ecology of Ghana. Fruit fly puparia obtained from incubation of 17 host fruit species were maintained in rearing cages for the emergence of parasitoid wasps. Four species of braconid parasitoids namely, Fopius caudatus (Szépligeti), Psyttalia cosyrae (Wilkinson), Psyttalia concolor (Szépligeti) and Diachasmimorpha fullawayi (Silvestri) were recovered. F. caudatus was the most abundant parasitoid (61.0%) reared from most host fruits while D. fullawayi was the least abundant (7.7%). The overall mean parasitism rate was 7.1% with the highest record in Annona senegalensis Pers., Sarcocepholus latifolium S. Bruce and Icacina senegalensis Juss. Ceratitis cosyra and Bactrocera invadens were the fruit fly species most commonly reared that produced F. caudatus, and to a lesser extent, P. cosyrae. The peak occurrence of the parasitoids coincided with the peak of the rains and the maturity period of many of the host fruits. This first inventory of tephritid parasitoids in Ghana provides critical baseline data for biological control efforts in the future.     

Bio-rational control of red flour beetle <Emphasis Type="Italic">Tribolium castaneum</Emphasis> (Herbst) (Coleoptera: Tenebrionidae) in stored wheat with Calneem<Superscript>®</Superscript> oil derived from neem seeds

The red flour beetle, Tribolium castaneum (Herbst), is one of the most serious secondary pests that feeds on a wide range of durable stored products including cereals, cereal products and other high value produce such as cocoa beans and dried fruits. Toxicity and protectant potential of Calneem^® oil derived from the seeds of the neem tree Azadirachta indica A. Juss. towards T. castaneum were evaluated in stored wheat in the laboratory using contact toxicity, grain treatment, persistency, progeny emergence and repellency assays. Calneem^® contains about 0.3% azadirachtin as its major active ingredient. The Calneem^® was applied at six dosages (0.1, 0.2, 0.5, 1.0, 2.0 and 3.0% v/v). The oil was emulsified with water using 0.07% soap. All dosages of Calneem^® oil were toxic and highly repellent to T. castaneum with an overall repellency in the range of 52–88%. The highest dosage of 3.0% of Calneem^® oil tested killed at least 90% of the beetles within 72 h on grain, and 88% mortality was obtained on filter paper. T. castaneum mortality was dose dependent. The development of eggs to adults on cracked wheat was significantly (P < 0.05) inhibited by Calneem^® oil treatments. The effectiveness of Calneem^® oil was significantly reduced by the length of storage after application. The results obtained suggest good potential for the practical use of Calneem^® oil as grain protectant for stored product pest control. The use of plant materials such as neem oil may be a safe, cost-effective method of grain preservation against pest infestation amongst low-resource poor farmers who store small amounts of grains.     

Efficacy of diatomaceous earth formulations against Callosobruchus maculatus (F.) (Coleoptera: Bruchidae) in Kersting’s groundnut (Macrotyloma geocarpum Harms): influence of dosage rate and relative humidity

The pulse beetle, Callosobruchus maculatus F. is a key pest to stored Kersting’s groundnut, Macrotyloma geocarpum Harms. There are many reports evaluating various diatomaceous earths (DEs) against stored product pests, but there is limited information on the efficacy of these materials against C. maculatus and none on Kerstings groundnut. Laboratory experiments were conducted to evaluate the efficacy of the DEs, Diatomenerde, Probe-A, Fossil shield, and Damol-D1 against C. maculatus in seeds of M. geocarpum. Each DE was applied at 0.50, 1.00, 1.50, and 2.00 g kg^?1, and each treatment infested with newly emerged C. maculatus in petri dishes. The set up was maintained at 50 and 80 % RH regimes at ambient temperature. Data were collected on adult mortality (at 24 h, 48 h, 7 days, and 14 days), oviposition, and progeny emergence of the beetles, and their effects on weight loss and viability of seeds. Probe-A proved the most effective against the beetle, followed by Damol-D1 and Fossil shield. Adult mortality increased progressively with the increasing dosage of DE and exposure time. Seeds treated at 2.00 or 1.50 g kg^?1 recorded significantly lower number of eggs and F1 emergence compared with the lower dosages in all DEs. Increased DE concentration consistently decreased seed weight loss due to low beetle infestation, but there was no significant effect on seed viability. DEs were more effective at 50 % RH than at 80 % RH. Probe-A or Damol-D1 applied at 1.50 or 2.00 g kg^?1 at 50 % RH is a viable alternative for preventing C. maculatus infestation in stored Kersting’s groundnut.     

Bio-insecticidal effectiveness of three formulations of diatomaceous earths against Callosobruchus maculatus (F.) (Coleoptera: Chrysomelidae) in stored cowpea

Journal of Plant Diseases and Protection - Three diatomaceous earths (DEs), InsectoSec®, Diatomeenerde Probe-A and Fossil Shield® 90.0, were tested in the laboratory against...     

Toxicity and protectant potential of Piper guineense (Piperaceae) and Senna siamea (Fabaceae) mixed with diatomaceous earth for the management of three major stored product beetle pests

There is a dearth of knowledge on the available sources of botanical products for smallholder farmers in Africa and their bioactivity against stored-product pests. Many locally available plants across Africa exhibit both promising insecticidal, medicinal activity and are nutrient rich yet remain underutilized. Laboratory studies on toxicity of powders of Senna siamea and Piper guineense alone or combined with diatomaceous earth (DE) to adult Sitophilus granarius, Tribolium castaneum and Acanthoscelides obtectus were conducted in stored grains. Adult mortality was observed up to 7 d while progeny production was recorded 6–10 weeks. Adult A. obtectus were most susceptible (LD₅₀ 0.0084% and 0.0696% wt/wt for S. siamea and P. guineense, respectively), followed by S. granarius. T. castaneum was most tolerant (LD₅₀ 0.6589% and 0.6829% wt/wt for S. siamea and P. guineense, respectively). Combination of plant powders and DE controlled the beetles faster compared to the plant powders alone. LT₅₀ ranged from 20 h to 101 h for T. castaneum exposed to 1.0% S. siamea and 1.0% DE, and 0.5% P. guineense and 1.0% DE, respectively. Botanicals caused significant reduction of F₁ adults compared to the control. The potential of using botanicals combined with DE to control stored-product insects is discussed.     

Toxicity and protectant potential of camphor,a major component of essential oil of Ocimum kilimandscharicum,against four stored product beetles

The biological activity of camphor, a major component of essential oil of the basil shrub, Ocimum kilimandscharicum, against the beetles, Sitophilus granarius, S. zeamais, Tribolium castaneum and Prostephanus truncatus, was investigated in the laboratory using contact toxicity, grain treatment and repellency assays. Camphor applied either topically, impregnated on filter papers or whole wheat and maize grains was highly toxic to all the four species. Beetle mortality was dosage-dependent with the highest doses of 100 mg/ filter paper and 100 mug/insect evoking over 93% and 100% mortalities, respectively, in S. granarius, S. zeamais and P. truncatus after 24 h exposure. Similar doses induced 70% and 100% mortality in T. castaneum. Camphor impregnated on the grain surface was more effective than on filter paper. There was, however, highly significant reduction in toxicity in grain after only 24 h following treatment. Development of eggs and immature stages within grain kernels, as well as progeny emergence, was completely inhibited in camphor-treated grain. Camphor was also highly repellent to the beetles with overall repellency in the range of 80 - 100%. The potential use of suitable products derived from O. kilimandscharicum as supplementary or alternative grain protectants against insect damage in traditional grain storage in developing countries is discussed.