Bruchus rufimanus | |
---|---|
Enlarged view of a broad bean beetle | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Arthropoda |
Class: | Insecta |
Order: | Coleoptera |
Infraorder: | Cucujiformia |
Family: | Chrysomelidae |
Genus: | Bruchus |
Species: | B. rufimanus |
Binomial name | |
Bruchus rufimanus Boheman, 1833 | |
Bruchus rufimanus, commonly known as the broadbean weevil, broadbean beetle, or broadbean seed beetle is a leaf beetle which inhabits crops and fields, as well as some homes. It is a pest of faba beans (Vicia faba L.). The adult beetles feed on pollen, while their larvae tunnel in seeds destroying crops and moving on to new ones once they dry out. The adult beetle, being one of the biggest of its genus, ranges from 3 to 5 mm in length.
The broadbean beetle, B. rufimanus is univoltine. It reproduces in spring in faba bean crops, lays eggs on the young pods, develops in the growing seeds and overwinters as adults in shelters, or in diapause as larva or pupa diapause in the stored seeds.
Adults are in reproductive diapause and overwinter in protected sites such as under tree barks, particularly of old, standing trees, hedgerows, lichen, and in forests [1] or leaf litter. [2] At early spring, they can be observed feeding on pollen and nectar of nearby flowers and particularly on Fabacae and Vicia spp.. Some B. rufimanus can survive during winter in larval or pupal diapause inside the seeds and terminate their diapause, finish their post-embryonic growth and emerge from the seeds after sowing. [3]
Males' sexual maturation is triggered by an increased proportion of light in the photoperiod, such that they are sexually mature when they colonize the field when the crop reaches leaf development. More specifically, a day length of 16h is required for the beetles to terminate their reproductive diapause. An optimal day length of 18h is found to induce diapause termination. [1]
Females are still in reproductive diapause when they colonize the field once crops reach flowering stage and day temperature reach 20 °C. They become sexually mature in a few days, as a result of both an increased duration of photophase and the ingestion of faba bean pollen and nectar (Tran and Huignard 1993).
Adults are extremely mobile during the day, and find refuge in resting sites in flowers and young leaves at night and early morning. They migrate from crop to crop following flower availability. Field density can vary. In France, numbers are around 20 adults/100 plants at the beginning of the colonization and 150 adults/100 plants at population peak when pressure is high.
Fields near overwintering sites such as woody and herbaceous environment, and storage facilities, present increased risk of B. rufimanus colonization, particularly in areas with high infestation the precedent year.
Once males and females are both sexually mature, mating is spread over a few weeks. Insects are active when temperature reaches 20 °C; temperatures above 25 °C are very favorable to their activity in the field whereas colder temperatures below 15 °C and wet weather limit insect mobility. Once fertilized, females B. rufimanus lay eggs on developing pods of faba beans. Rain, wind and temperatures below 20 °C put on hold the oviposition process. Eggs are laid predominantly on the lowest parts of the plant. [2] Eggs are small (< 2mm diameter), white-yellowish. A maximum of ten eggs per pod is observed. Females lay between 50 and 100 eggs. Rain might increase egg mortality.
After about 10 days (1–3 weeks depending on temperatures), larvae hatch and bore directly throughout the pod walls and develop within the seed. Larvae are thus protected from biological and chemical control. Larval development lasts two to three months. Before entering its pupal stage, the larva cuts a circular cap. After around ten days of pupal stage, the adult emerges from the seeds. Because mating and oviposition are spread over a few weeks, adults can emerge before or after harvest.
Although B. rufimanus does not directly affect faba bean yield, it alters the aesthetic quality of the seeds as well as its germinative properties and ensuing yield is therefore an issue for human consumption and seed markets. A maximum 3% damage threshold is set for seeds targeting market for human consumption. Damaged seeds (seeds from which adults have emerged) might have lower germination rates with 13% reduced germination observed in the lab, but no difference observed in the field. [4] Yield from infested beans are lower (-45% to -70%) than for healthy ones (Epperlein, 1992). In addition, damaged seeds have increased susceptibility to rust and root diseases. [4]
Additionally, the presence of living insects on seeds are an issue for the export market as no living insects are allowed for export. The presence of beetles in the seeds after harvest thereby decreases faba bean commercial value.
This section needs additional citations for verification .(July 2019) |
The larval stages of B. rufimanus occur inside the seeds, and are therefore protected from any control measures, including chemical control. Bruchus rufimanus is most vulnerable at the adult stage. Most control measures have therefore targeted adults either at colonization stage in the field or at emergence in storage facilities. Control measures have been focused on direct control with insecticides, but restrictions and removal from market due to environmental concerns have increased the need for alternative measures.
Because of their larval development inside the seeds which are protected by the pods, most inventorying methods are based on population of B. rufimanus adult in the field or at emergence. Adult population density can be estimated by counts on plants at field colonization. The development semiochemical attractants trapping systems for both monitoring and pest control has received particular interest in ongoing research on the beetle. [2] Egg density can be estimated on young developing pods (>2 cm) during the oviposition period. Eggs are however small (<1mm length), green-yellowish, therefore difficult to observe. In addition, population estimate are difficult to obtain as egg laying is spread over time until 5–10 days after the end of flowering (BBCH 77). After harvest, seed quality can be observed manually at harvest and characterized according to pest damage (healthy, with no trace of damage/containing developing larvae/trace of emerged B. rufimanus adult (a hole in the seed). Alternative methods exist to sort the seeds: sorting can be done using differences in seed density due to the presence of the developing larva or of the hole left by the emerged adult, estimation of damages seeds can be done by tomography analysis. Additionally, the end of larval and pupal diapause and therefore the emergence of B. rufimanus can be induced via a solution of NaOCl and chinosol in 7 days at 30 °C, [5] allowing the estimation of an overall infestation rate can be assessed.
In Europe, pyrethroids and neonicotinoids have been used against B. rufimanus. Because of the faba bean crop biology and its attraction to pollinators at flowering stage, restrictions on pesticides uses have been introduced in Europe. It is particularly advised to spray in absence of pollinators in the early morning and evening. In addition, due to B. rufimanus' biology, a temperature threshold combined with crop development stage can be used to increase the success of chemical treatments. Adult B. rufimanus activity increases with temperature, so that treatment efficiency might increase when maximum day temperatures are over 20°C during four consecutive days after treatment (Arvalis, 2016). Adult B. rufimanus activity increases with temperature, so that treatment efficiency might increase when maximum day temperatures are over 20°C during four consecutive days after treatment. The end of blooming indicates the end of adult activity in the field. This stage is therefore a threshold marking the end of insecticide application and occurs no later than five days after last blooming. Forecasting systems (Bruchi-LIS, Arvalis, France and BruchidCast, Syngenta, UK) have been developed to optimize insecticide applications based on temperature and crop stage.
Although the measures taken in storage facilities do not decrease the proportion of damaged seeds, they limit the densities of emerging insects and therefore the pressure for the coming year. Such measures will be especially efficient in storage as most B. rufimanus have then not yet emerged and are still developing in the seeds. Early harvest could therefore be recommended for best control measures in storage facilities.
The pressure from B. rufimanus seems unaffected by management practices and cultivar although little data is available. Because B. rufimanus biology is highly linked to crop development and climatic conditions, pest damage and pressure the next year can vary according to sowing and harvesting date. In addition, sanitation can help decreasing the source of B. rufimanus in production areas.
Parasitoids have been found to parasitize B. rufimanus eggs: Chremylus rubiginosus and Triaspis thoracicus (family: Braconidae), and Dinarmus acutus (family: Pteromalidae). Their larvae develop into B. rufimanus larvae and adults emerge from the seed, leaving a small emergence hole in the seed (smaller than for B. rufimanus). Generalist predators on faba bean leaves such as spiders might feed on B. rufimanus eggs and contribute to their biological control although no data was found on their potential impact on the population size or growth.
Helicoverpa zea, commonly known as the corn earworm, is a species in the family Noctuidae. The larva of the moth Helicoverpa zea is a major agricultural pest. Since it is polyphagous during the larval stage, the species has been given many different common names, including the cotton bollworm and the tomato fruitworm. It also consumes a wide variety of other crops.
The Colorado potato beetle is also known as the Colorado beetle, the ten-striped spearman, the ten-lined potato beetle, or the potato bug. It is a major pest of potato crops. It is about 10 mm long, with a bright yellow/orange body and five bold brown stripes along the length of each of its elytra. Native to the Rocky Mountains, it spread rapidly in potato crops across America and then Europe from 1859 onwards.
The drugstore beetle, also known as the bread beetle, biscuit beetle, and misnamed as the biscuit weevil, is a tiny, brown beetle. It can be found infesting a wide variety of dried plant products, where it is among the most common non-weevils to be found. It is the only living member of the genus Stegobium. It belongs to the family Ptinidae, which also includes the deathwatch beetle and furniture beetle. A notable characteristic of this species is the symbiotic relationship the beetles have with the yeast they carry, which are transmitted from female to larvae through the oviduct.
The silverleaf whitefly is one of several species of whitefly that are currently important agricultural pests. A review in 2011 concluded that the silverleaf whitefly is actually a species complex containing at least 40 morphologically indistinguishable species.
The Mexican bean beetle is a species of lady beetle that can be an agricultural pest. It is one of the few North American lady beetles that feed on plants rather than other insects. It is found throughout Mexico and the eastern United States, and is abundant in the wetter and more heavily irrigated areas west of the Rocky Mountains. It does not tolerate extremely dry areas.
Delia flies are members of the Anthomyiidae family within the superfamily Muscoidae. The identification of different species of Delia can be very difficult for non-specialists as the diagnostic characteristics used for immature and/or female specimens may be inconsistent between species. Past taxonomic keys were not as comprehensive in their identification of Delia specimens; they were either too reliant on genetic characteristics, focused solely on a specific life stage, or were focused only on certain species. However current taxonomic keys aim to be more thorough by not only including morphological diagnostics for males, females, and immature specimens of various species, but also their genetic make-up or molecular barcode.
The European corn borer, also known as the European corn worm or European high-flyer, is a moth of the family Crambidae. It is a pest of grain, particularly maize. The insect is native to Europe, originally infesting varieties of millet, including broom corn. The European corn borer was first reported in North America in 1917 in Massachusetts, but was probably introduced from Europe several years earlier. Since its initial discovery in the Americas, the insect has spread into Canada and westwards across the United States to the Rocky Mountains.
Callosobruchus maculatus is a species of beetles known commonly as the cowpea weevil or cowpea seed beetle. It is a member of the leaf beetle family, Chrysomelidae, and not a true weevil. This common pest of stored legumes has a cosmopolitan distribution, occurring on every continent except Antarctica. The beetle most likely originated in West Africa and moved around the globe with the trade of legumes and other crops. As only a small number of individuals were likely present in legumes carried by people to distant places, the populations that have invaded various parts of the globe have likely gone through multiple bottlenecks. Despite these bottlenecks and the subsequent rounds of inbreeding, these populations persist. This ability to withstand a high degree of inbreeding has likely contributed to this species’ prevalence as a pest.
The Angoumois grain moth is a species of the Gelechiidae moth family, commonly referred to as the "rice grain moth". It is most abundant in the temperate or tropical climates of India, China, South Africa, Indonesia, Malaysia, Japan, Egypt and Nigeria, with its location of origin being currently unknown. It is most commonly associated as a pest of field and stored cereal grains as they burrow within the kernel grains of crop plants, rendering them unusable for human consumption. By laying eggs between the grains themselves and hatching at a later time, often during the processing, transportation or storage stages, the moth can be transported to households or countries presently free of Angoumois grain moth infestations. Thus, constant protection against the Angoumois grain moth is required for grain up till the time of consumption.
Empoasca decipiens is a species of leafhopper belonging to the family Cicadellidae subfamily Typhlocybinae. The adults reach 3–4 millimetres (0.12–0.16 in) of length and a are homogenously green with whitish markings on its pronotum and vertex. E. decipiens is commonly referred to as the “green leafhopper” because of its colouration. The absence of clear stripes along the forewings can easily distinguish it from the similar leafhopper species E. vitis, but distinguishing it from other leafhoppers with the same colouration requires examination under a microscope. It is present in most of Europe, in the eastern Palearctic realm, in North Africa, in the Near East, and in the Afrotropical realm. Both nymphs and adults of this small insect are considered to be a very destructive pests on field crops, vegetables and greenhouse plants.
Cerotoma trifurcata is a species of beetle in the Chrysomelidae family that can be found in the Eastern and West United States.
Bruchus is a genus of beetles in the leaf beetle family, Chrysomelidae. They are distributed mainly in the Palearctic, especially in Europe. Several occur in other parts of the world, such as North America, Africa, and Australia, as introduced species. Several species are notorious agricultural pests.
Curculio elephas is a species of beetle in the family Curculionidae, the true weevils. It is known commonly as the chestnut weevil. It is a serious pest of chestnut in Europe.
Acanthoscelides obtectus, the bean weevil, is a species of bruchid beetle. The species was described in 1831 by Thomas Say.
Araecerus fasciculatus, the coffee bean weevil, is a species of beetle (Coleoptera) belonging to the family Anthribidae. Despite its name, it affects a wide range of stored products and some field crops and is accredited with consuming more than 100 different kinds of stored goods. This polyphagous insect is often found in stored crops such as: corn, cassava, sweet potatoes, nutmeg, dried fruits and various nuts. Through trade it has become cosmopolitan in its distribution and is considered an economically important global pest. A. fasciculatus causes significant damage to stored food goods, can result in loss of mass quantities of product and can reduce the quality of the stored goods.
Callosobruchus is a genus of beetles in the family Chrysomelidae, the leaf beetles. It is in the subfamily Bruchinae, the bean weevils. Many beetles in the genus are well known as economically important pests that infest stored foodstuffs.
Potato leafhopper belongs to family Cicadellidae and genus Empoasca within order Hemiptera. In North America they are a serious agricultural pest. Every year millions of dollars are lost from reduced crop yields and on pest management. Crops that are impacted the most are potatoes, clover, beans, apples and alfalfa.
Sitona lineatus, commonly known as the pea leaf weevil is a species of weevil with a Palearctic distribution. It is a common pest of beans, peas, and other plants in the family Fabaceae. Adult beetles of S. lineatus measure 3.4-5.3 mm in length. They are characterized by a series of colored scales arranged in alternating lines (striae) on the elytra; it is from this characteristic where the species gets its name lineatus meaning 'lined' or 'striped'. The head and pronotum also have fine pointed setae amongst the scales. The antennae are clubbed, pointed and preceded by 7 segments. The femora is dark, but tibiae and tarsi are red. As a member of Order Coleoptera (beetles) their forewings are modified to form hardened covers over the thorax and abdomen, with the hindwings for flight underneath.
Bruchus pisorum, known generally as pea weevil, is a species of leaf beetle in the family Chrysomelidae. Other common names include the pea beetle and pea seed beetle. It is found in Europe and Northern Asia, North America, and temperate Asia.
A storage pest is an insect or other animal that damages or destroys stored food or other stored valuable organic matter. Insects are a large proportion of storage pests with each type of crop having specific insects that gravitate towards them such as the genus Tribolium that consists of insects such as Tribolium castaneum or Tribolium confusum which damage flour crops primarily.