Papers by C. Akotsen-mensah
Peach production is a major industry in Alabama and many other southeastern states of the United ... more Peach production is a major industry in Alabama and many other southeastern states of the United States. Over 40,000 acres of fresh and processed peaches worth $65 million are produced annually in Alabama, Georgia, and South Carolina. In Alabama alone, approximately 22 million pounds of peaches were produced in 2001 with a market value of about $12 million. The plum curculio, Conotrachelus nenuphar Herbst (Coleoptera: Curculionidae) is the most serious economic pest of peaches in Alabama and other parts of the southeastern U.S. This study was conducted to develop and implement cost-effective and environmentally friendly pest management practices for plum curculio. Specific objectives are: (1) Field evaluation of traps and lures for monitoring plum curculio in Alabama peaches, (2) Laboratory evaluation of Fadamiro nurtured, mentored and instilled in me a sense of discipline and work ethics that has inspired me to achieve the unimaginable no matter the obstacles. I am highly indebted to the rest of my committee members, namely Drs. Arthur Appel, Louis Jackai, Foshee Wheeler, Mr. Robert Boozer and the outside reader of my dissertation Dr. Floyd Woods. I am particularly, grateful to Mr. Robert Boozer; Research and Extension Horticulturist at Chilton Research and Extension Centre (CREC), Clanton, AL., who has been a great source of motivation and his immense contribution and expertise which he made available to me can not go without my recognition. The head, Dr. Arthur Appel and staff of the Entomology and Plant Pathology Department, Auburn University are worthy of mentioning for their enormous support in many diverse ways. I am personally grateful to the Superintendent, Mr. James Pitts and all the staff of CREC for the opportunity and assistance to work at the Centre. The contributions of Drs Li Chen and Kavita Sharma, both postdoctoral fellows in our laboratory and my lab colleagues namely,
Pocapharaptinus gen. nov. and eight new species, P. müllerae sp. nov., P. harrisoni sp. nov., P. ... more Pocapharaptinus gen. nov. and eight new species, P. müllerae sp. nov., P. harrisoni sp. nov., P. akotsenorum sp. nov., P. capensis sp. nov., P. soutpanensis sp. nov., P. lachnos sp. nov., P. aboakyer sp. nov., and P. acanthus sp. nov. are described from South Africa. The genus is distinguished by the pronotal surface being densely covered with flocculent, wooly, tan colored setae obscuring the cuticular surface except anteriomedially, where the bare cuticle is variably triangular in shape. All species are illustrated, described, diagnosed and an identification key provided. The biogeography and relationships of this genus to other Ptinidae are also discussed.
The yellowmargined leaf beetle, Microtheca ochroloma Stl (Chrysomelidae) is the most damaging pes... more The yellowmargined leaf beetle, Microtheca ochroloma Stl (Chrysomelidae) is the most damaging pest of organic crucifer production in Alabama and other parts of the southern United States. Currently, organic crucifer growers lack monitoring tools necessary for proper targeting of pest management tactics. Therefore, alternative approaches such as pest prediction models are essential for anticipating insect activity and its migration. The goal of this study was to develop a temperature-based pest prediction model that could be used in predicting migration of M. ochroloma into vegetable fields. Laboratory experiments were conducted to determine rates of larval and pupal development and adult activity at constant temperatures ranging from 10 - 35C. Field experiments were carried out to validate the model.
Hemipteran insect pests like leaf-footed bugs Leptoglossus phyllopus, brown stink bugs Euchistus ... more Hemipteran insect pests like leaf-footed bugs Leptoglossus phyllopus, brown stink bugs Euchistus servus and green stink bugs Nezera viridula are important pests of a wide range of fruit and vegetable crops in the southeastern United States. The increasing adoption of post-FQPA regulations for many fruit crops combined with renewed interest in organic agriculture in much of the southeast, have made it necessary to evaluate other alternate pest management tools such as trap crops to manage these emerging pests. Field studies were conducted in central Alabama during winter and summer of 2011 and 2012 to evaluate different trap crops for their potential use for managing these pests in peaches. The winter trap crops are oats, winter peas, rye, hairy vetch, wheat and triticale. The results in both seasons and years showed that trap crops can be used to manage stink and leaf-footed bugs in peaches. Over 95% of all hemipteran insects recorded were L. phyllopus. The brown stink bug E. servus...
Experiments were conducted to determine the influence of soil and weed management practices on pl... more Experiments were conducted to determine the influence of soil and weed management practices on plum curculio (PC), Conotrachelus nenuphar Herbst development and emergence. The following treatments were evaluated in plots (plot size: 3 m 3 m) in peach orchard: soil covered with pine bark, soil covered with centipede grass (Eremochloa ophiuroides), natural weedy soil, and bare soil (weeds removed with herbicide sprays). The results showed that adult PCs did not differ in their mean development time from larva to adult stage in the different treatments. However, significantly fewer adult PCs emerged from soil covered with centipede grass than from all other treatments.
Pest Management Science, 2011
Plum curculio (PC), Conotrachelus nenuphar (Herbst.), is an important pest of peaches in the sout... more Plum curculio (PC), Conotrachelus nenuphar (Herbst.), is an important pest of peaches in the southeastern United States. Commercially acceptable control of this insect is typically achieved by weekly or biweekly application of broad-spectrum conventional insecticides, resulting in 6-12 sprays per season. Experiments were conducted in a peach orchard in Alabama during 2007-2009 to compare the conventional calendar-based insecticide spray program involving weekly applications of phosmet with three different reduced spray programs using three targeted (well-timed) insecticide sprays (TIS) of phosmet, permethrin or thiamethoxam applied in an alternated fashion. All three TIS programs significantly reduced PC damage at harvest compared with the untreated control in two of the three years (2008 and 2009). Fruit damage due to stink bugs, which are emerging pests of peaches in the region, was also significantly reduced in the TIS programs in both years. In a separate trial in which one of the TIS programs (three targeted sprays of phosmet) was evaluated in a larger peach block in 2009, percentage fruit damage due to PC increased from < 1% in June to ~4% in late July. All the TIS programs evaluated provided effective control of PC and represent potential alternatives to the conventional weekly spray program in peaches with concomitant reduction in insecticide usage and associated costs. However, an additional spray may be necessary for effective control of PC and stink bugs in late-season peach varieties.
Journal of Economic Entomology, 2010
The plum curculio, Conotrachelus nenuphar (Herbst) (Coleoptera: Curculionidae), is a key pest of ... more The plum curculio, Conotrachelus nenuphar (Herbst) (Coleoptera: Curculionidae), is a key pest of peaches, Prunus persica (L.) Batsch, in North America. We evaluated the effectiveness of two widely used trap types (pyramid versus Circle traps) and commercially available synthetic lures for monitoring the pest in two peach orchards in Alabama during 2008 and 2009. The lures evaluated alone or in combinations included benzaldehyde (BZ) (a component of fruit odor), plum essence (PE) (a mixture of fruit odor extracted from food grade plum), and grandisoic acid (GA) (a male-produced aggregation pheromone of plum curculio). In general, pyramid traps captured more plum curculio adults than Circle traps, particularly during the Þrst generation. Trap performance was improved numerically by the addition of BZ, PE, or GA alone (single lures) and was signiÞcantly enhanced by the addition of the combined BZ ϩ PE lure. In both Þrst and second generations, the combined BZ ϩ PE lure increased plum curculio captures (signiÞcant in some trials) over unbaited traps and traps baited with single lures by Ϸ 1.5Ð21-fold and had the highest response indices (RIs), which is indicative of high attractiveness. The combined BZ ϩ GA lure and the three-component BZ ϩ PE ϩ GA lure also captured numerically more plum curculio adults than unbaited traps or traps baited with single lures but the differences were rarely signiÞcant. Analysis of ratios of interaction suggests the possibility of synergistic interactions between BZ and PE and between BZ and GA; however, additive effects were concluded due to high sample errors. These results are discussed in relation to the physicochemical properties of the lures and the potential of using baited monitoring traps to aid plum curculio management decisions in peach orchards.
Florida Entomologist, 2012
Plum curculio, Conotrachelus nenuphar Herbst (Coleoptera: Curculionidae), is a key pest of peache... more Plum curculio, Conotrachelus nenuphar Herbst (Coleoptera: Curculionidae), is a key pest of peaches in the southeastern United States. Part of its life cycle, specifically, the pre-pupal, pupal and pre-adult stages are spent in the soil. Experiments were conducted in 2 peach orchards to evaluate the effects of some common orchard weed management practices on the development of the soil dwelling life stages of plum curculio. Four common orchard weed management practices (treatments) were evaluated in plots (3 m × 3 m) located under peach tree canopies: centipede grass, Eremochloa ophiuroides (Munro) understory (soil covered with centipede grass); weed free understory (bare soil, weeds removed with herbicide sprays); weedy (natural weeds) understory; and pine bark understory (soil covered with pine bark). Fewer numbers of adult plum curculio emerged from the centipede grass understory plots compared with weed free, weedy or pine bark treated understories. Similar results were obtained in the greenhouse: fewer adults emerged from centipede grass than bare soil in spring 2009. Possible reasons for the lower emergence of plum curculio in centipede grass plots are proposed.
Florida Entomologist, 2013
We evaluated 3 species of predacious mites (Acari: Phytoseiidae), Galendromus occidentalis (Nesbi... more We evaluated 3 species of predacious mites (Acari: Phytoseiidae), Galendromus occidentalis (Nesbitt), Phytoseiulus persimilis Athias-Henriot and Neoseiulus californicus (McGregor), as biological control agents for citrus red mite, Panonychus citri (McGregor) (Trombidiformes: Tetranychidae), on citrus in southern Alabama. Three separate experiments were carried out during 2008 and 2011 to evaluate various factors (i.e. release rate, release frequency and initial prey density) that may impact the performance of the predacious mites. In the first experiment conducted in 2008 on trees with moderate initial prey densities (i.e. < 4 P. citri motiles per leaf), one single release of P. persimilis or G. occidentalis at a rate of 100 or 200 per tree effectively prevented the prey from exceeding the economic threshold (5 motiles/leaf) for the entire duration (35 d) of the experiment. The result of the second experiment in 2008 on trees with high initial prey densities (i.e. ≥ 5 motiles per leaf) showed that 2 releases of P. persimilis or G. occidentalis at a rate of 100 or 200 per tree per release could not provide adequate suppression of P. citri below the economic threshold. In both experiments, P. citri densities were significantly lower in most predacious mite treatments compared to the control (no release). Also, lower P. citri densities were recorded at the higher release rate (200 per tree) compared to the lower rate, but this was only significant in a few cases. The third experiment conducted in 2011 in large plots on trees with low initial P. citri densities (i.e. < 1 motile per leaf) showed that 2 releases of N. californicus or P. persimilis at a rate of 200 per tree per release effectively maintained P. citri at low densities (< 1.5 motiles per leaf) throughout the duration (56 d) of the experiment. Limited observations in spring 2012 confirmed the establishment of the predacious mites released in the 2011 study. These results showed that all 3 phytoseiid species were effective in reducing P. citri densities on citrus. However, initial prey density may be an important factor influencing their performance.
Chemoecology, 2010
We used the electroantennogram (EAG) technique to compare the antennal sensitivity of both sexes ... more We used the electroantennogram (EAG) technique to compare the antennal sensitivity of both sexes of the giant swallowtail butterfly, Papilio cresphontes to four doses (1, 10, 100, and 1,000 lg) of the leaf essential oils of Zanthoxylum clava-herculis and Ptelea trifoliata (key host plants) and Sassafras albidum (a marginal or non-host plant). The main hypothesis tested was that P. cresphontes will show greater olfactory sensitivity to volatiles of the key host plants than to volatiles of the marginal host plant, in particular at low doses. At the lower doses, extract of the key host plant, Z. clava-herculis elicited greater EAG responses in both sexes than extracts of the remaining two plants. At higher doses, however, extracts of P. trifoliata and S. albidum elicited greater EAG responses than extract of Z. clava-herculis. These results partly support our hypothesis and may suggest that Z. clava-herculis is a more preferred host plant of P. cresphontes than P. trifoliata. In general, female butterflies showed greater EAG responses than males to the three plant extracts at the higher doses. Preliminary coupled gas chromatographyelectroantennogram (GC-EAD) tests revealed four components each from Z. clava-herculis and P. trifoliata (three peaks common to both extracts) and seven from S. albidum (one shared with Z. clava-herculis) which elicited GC-EAD activity in P. cresphontes females, but the peaks were un-indentified because most were detected in trace amounts. In addition, the chemical composition of the leaf essential oil of Z. clava-herculis was analyzed by GC-MS. The leaf essential oils consisted of 25 components, largely menthane monoterpenoids, dominated by limonene and 1,8-cineole, but neither of the two major components elicited significant GC-EAD response in P. cresphontes. These results are discussed in relation to host-plant selection in P. cresphontes.
The plum curculio, Conotrachelus nenuphar (Herbst) (Coleoptera: Curculionidae), is a key pest of ... more The plum curculio, Conotrachelus nenuphar (Herbst) (Coleoptera: Curculionidae), is a key pest of peaches, Prunus persica (L.) Batsch, in North America. Captures of adult weevils in unbaited pyramid traps recorded annually from 2000 to 2008 in an unmanaged peach orchard in central Alabama were used to determine its seasonal occurrence and to develop predictive degree-day models. Spring migration of plum curculio began at bloom (early to mid-March). Linear, polynomial, and three-parameter Weibull functions were tested to describe the relationship between weekly trap
capture and cumulative degree-day (DD). Criteria used to select the best models were the smallest
Akaike information criterion and highest R2 values. A sixth-order polynomial function Þtted best to
seasonal trap captures and cumulative DDs and revealed two major seasonal peaks with the Þrst
(spring generation) and second (summer generation) peaks occurring at cumulativeDDsof245 and
1105 (base 10C, bioÞx of 1 January), respectively. A potential third (late summer generation) peak was observed at 1758 DDs. The sixth-order polynomial model predicted the first trap capture to occur at cumulative DD of 99 (base 10C, biofix of 1 January). The three-parameter Weibull model predicted the first trap and first peak (spring generation) trap captures to occur at mean cumulative
DDs of 108.02 9 and 220.07 16, respectively. Validation of the models in the unmanaged orchard in 2009 and 2010 and in a second unmanaged orchard (located 1.6 km from the first) in 2009 showed that the polynomial and Weibull were within 7 d in their predictions of the first and peak trap captures of the spring population. Validation results showed that both models successfully predicted the first trap capture in one out of three scenarios and the peak trap capture in two out of three scenarios. The performance of the models is discussed in relation to management of plum curculio in central Alabama.
We investigated the abundance and diversity of entomofauna associated with citrus orchards in two... more We investigated the abundance and diversity of entomofauna associated with citrus orchards in two different agroecological zones of Ghana. Malaise traps, flight interception traps, pitfall traps, chemical ʽʽknock down'' and visual observation were used for data collection. We recorded a total of 20, 285 individual insects belonging to 387 species from 107 families and 13 orders. Although, several species of insects were common to both agroecological zones, some were more specific to Original Research Article
The present study investigates the effects of some climatic factors on insects associated with ci... more The present study investigates the effects of some climatic factors on insects associated with citrus orchards in two different agro-ecological zones in Ghana. The study showed that, climatic factors affected insects differently in different agro-ecological zones. There was a negative and highly significant (P˂0.01) correlation between insect abundance and rainfall in the Coastal Savannah zone whereas the correlation between mean temperature and insect abundance was negative and significant (P˂0.05) in the Semi-Deciduous Rain Forest zone. Numbers of insect species peaked differently in some months during the study period due to favourable climatic conditions for their reproduction, growth and activities. The month of February was most favourable for the insects in the Semi-Deciduous Rain Forest zone whiles January was most favourable for the Coastal Savannah zone. Similarly, some months were more favourable for pests of citrus in Ghana; January and February for Ceratitis ditissima a...
Sesame (Sesamum indicum L.) Pedaliaceae is produced mainly in developing countries where abundant... more Sesame (Sesamum indicum L.) Pedaliaceae is produced mainly in developing countries where abundant and inexpensive labour is available and usually by small holders. It is cultivated for its edible seeds which is high in nutritious fatty acids. In Africa sesame has in recent years been promoted to diversify agricultural production especially in the Sahel region. It has the potential to become an important field crop in Ghana especially in the drier regions. Unavailable field data on constraints to sesame production including its insect pests may be the reason for its non-commercial cultivation in Ghana. A preliminary survey of arthropods associated with sesame, was conducted in the transitional zone of Ghana during the 2009 growing season. In order to achieve maximum natural infestation, no conscious control measure was adopted. A wide spectrum of arthropods including chewers, suckers, pollinators, scavengers and predators were found. In all 60 insect species and 11 spiders were colle...
Outlooks on Pest Management, 2015
Objective: The susceptibility of four economically important mango varieties (Kent, Keith, Palmer... more Objective: The susceptibility of four economically important mango varieties (Kent, Keith, Palmer and Haden) in Ghana to the attack by Bactrocera invadens was assessed through a series of laboratory-based choice and no-choice experiments, as well as some fruit quality parameters. The developmental periods of immature stages of flies in the varieties were also determined. Methodology and results: Susceptibility was determined by counting and comparing the number of puparia recovered from the different varieties after exposure to the flies in cages. Kent was found to be the most susceptible, followed by Palmer, Haden and Keith. Flies took significantly longer periods to complete development on the least susceptible variety (Keith) (25.53 ± 2.3 days), than on the most susceptible variety (Kent) (19 ± 2.3 days). Significant differences (P ˂ 0.05) were also observed in the peel thickness, firmness, Percent Titratable Acidity (% T.A.) and Total Soluble Solids (TSS) of the four varieties. Conclusion and application: Keith was found to be the least susceptible variety to B. invadens followed by Haden, Palmer and Kent was the most susceptible variety. The differences observed in varietal susceptibility suggest that potentials exist for further genetic improvement to develop mango varieties that may be more tolerant to B. invadens, and could be incorporated into an integrated management strategy against the pest because of the added advantages of it being easy to use, economical and compatible with other methods of control.
This study was conducted with the primary objective of comparing the attractiveness of crude aque... more This study was conducted with the primary objective of comparing the attractiveness of crude aqueous leaf extracts of an exotic spice plant Pimenta dioica L. with two commonly used attractants: methyleugenol and sweet orange citrus (Citrus sinensis Osbeck) juice for the Africa invader fruit fly
Bactrocera invadens Drew, Tsuruta & White (Diptera: Tephritidae) in a citrus plantation. No significant
differences were observed among the tested concentrations (5, 10, 15 and 20% wt/vol) for most of the sampling days indicating that none of the concentrations was superior over the other in attracting B. invadens. The performance of the extracts was comparable with the synthetic methyl eugenol,
particularly, during the first four days of placing the attractants in the field. Traps baited with synthetic methyl eugenol lure mixed with cypermethrin technical grade in a ratio of 4:1 v/v captured and killed significantly more adult B. invadens compared with traps baited with matured sweet orange citrus juice of about 10% brix. We have therefore shown for the first time that field populations of adult male B. invadens can be attracted to crude aqueous leaf extracts of P. dioica. These results suggest that leaf extracts of P. dioica can be used to detect and control B. invadens in citrus plantations.
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Papers by C. Akotsen-mensah
capture and cumulative degree-day (DD). Criteria used to select the best models were the smallest
Akaike information criterion and highest R2 values. A sixth-order polynomial function Þtted best to
seasonal trap captures and cumulative DDs and revealed two major seasonal peaks with the Þrst
(spring generation) and second (summer generation) peaks occurring at cumulativeDDsof245 and
1105 (base 10C, bioÞx of 1 January), respectively. A potential third (late summer generation) peak was observed at 1758 DDs. The sixth-order polynomial model predicted the first trap capture to occur at cumulative DD of 99 (base 10C, biofix of 1 January). The three-parameter Weibull model predicted the first trap and first peak (spring generation) trap captures to occur at mean cumulative
DDs of 108.02 9 and 220.07 16, respectively. Validation of the models in the unmanaged orchard in 2009 and 2010 and in a second unmanaged orchard (located 1.6 km from the first) in 2009 showed that the polynomial and Weibull were within 7 d in their predictions of the first and peak trap captures of the spring population. Validation results showed that both models successfully predicted the first trap capture in one out of three scenarios and the peak trap capture in two out of three scenarios. The performance of the models is discussed in relation to management of plum curculio in central Alabama.
Bactrocera invadens Drew, Tsuruta & White (Diptera: Tephritidae) in a citrus plantation. No significant
differences were observed among the tested concentrations (5, 10, 15 and 20% wt/vol) for most of the sampling days indicating that none of the concentrations was superior over the other in attracting B. invadens. The performance of the extracts was comparable with the synthetic methyl eugenol,
particularly, during the first four days of placing the attractants in the field. Traps baited with synthetic methyl eugenol lure mixed with cypermethrin technical grade in a ratio of 4:1 v/v captured and killed significantly more adult B. invadens compared with traps baited with matured sweet orange citrus juice of about 10% brix. We have therefore shown for the first time that field populations of adult male B. invadens can be attracted to crude aqueous leaf extracts of P. dioica. These results suggest that leaf extracts of P. dioica can be used to detect and control B. invadens in citrus plantations.
capture and cumulative degree-day (DD). Criteria used to select the best models were the smallest
Akaike information criterion and highest R2 values. A sixth-order polynomial function Þtted best to
seasonal trap captures and cumulative DDs and revealed two major seasonal peaks with the Þrst
(spring generation) and second (summer generation) peaks occurring at cumulativeDDsof245 and
1105 (base 10C, bioÞx of 1 January), respectively. A potential third (late summer generation) peak was observed at 1758 DDs. The sixth-order polynomial model predicted the first trap capture to occur at cumulative DD of 99 (base 10C, biofix of 1 January). The three-parameter Weibull model predicted the first trap and first peak (spring generation) trap captures to occur at mean cumulative
DDs of 108.02 9 and 220.07 16, respectively. Validation of the models in the unmanaged orchard in 2009 and 2010 and in a second unmanaged orchard (located 1.6 km from the first) in 2009 showed that the polynomial and Weibull were within 7 d in their predictions of the first and peak trap captures of the spring population. Validation results showed that both models successfully predicted the first trap capture in one out of three scenarios and the peak trap capture in two out of three scenarios. The performance of the models is discussed in relation to management of plum curculio in central Alabama.
Bactrocera invadens Drew, Tsuruta & White (Diptera: Tephritidae) in a citrus plantation. No significant
differences were observed among the tested concentrations (5, 10, 15 and 20% wt/vol) for most of the sampling days indicating that none of the concentrations was superior over the other in attracting B. invadens. The performance of the extracts was comparable with the synthetic methyl eugenol,
particularly, during the first four days of placing the attractants in the field. Traps baited with synthetic methyl eugenol lure mixed with cypermethrin technical grade in a ratio of 4:1 v/v captured and killed significantly more adult B. invadens compared with traps baited with matured sweet orange citrus juice of about 10% brix. We have therefore shown for the first time that field populations of adult male B. invadens can be attracted to crude aqueous leaf extracts of P. dioica. These results suggest that leaf extracts of P. dioica can be used to detect and control B. invadens in citrus plantations.