The plum curculio (''Conotrachelus nenuphar'') is a

true weevil True most commonly refers to truth, the state of being in congruence with fact or reality. True may also refer to: Places * True, West Virginia, an unincorporated community in the United States * True, Wisconsin, a town in the United States * T ...

native to the regions east of the

Rocky Mountains The Rocky Mountains, also known as the Rockies, are a major mountain range and the largest mountain system in North America. The Rocky Mountains stretch in straight-line distance from the northernmost part of western Canada, to New Mexico in ...

in the

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territorie ...

and

Canada Canada is a country in North America. Its ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, covering over , making it the world's second-largest country by tot ...

. It is notorious for destroying fruits if left uncontrolled. Conotrachelus nenuphar

Life stages

A female curculio uses a number of hosts to lay her

eggs Humans and human ancestors have scavenged and eaten animal eggs for millions of years. Humans in Southeast Asia had domesticated chickens and harvested their eggs for food by 1,500 BCE. The most widely consumed eggs are those of fowl, especial ...

in, including

plum A plum is a fruit of some species in ''Prunus'' subg. ''Prunus'.'' Dried plums are called prunes. History Plums may have been one of the first fruits domesticated by humans. Three of the most abundantly cultivated species are not found i ...

peach The peach (''Prunus persica'') is a deciduous tree first domesticated and cultivated in Zhejiang province of Eastern China. It bears edible juicy fruits with various characteristics, most called peaches and others (the glossy-skinned, non-fu ...

es,

apple An apple is an edible fruit produced by an apple tree (''Malus domestica''). Apple fruit tree, trees are agriculture, cultivated worldwide and are the most widely grown species in the genus ''Malus''. The tree originated in Central Asia, wh ...

pear Pears are fruits produced and consumed around the world, growing on a tree and harvested in the Northern Hemisphere in late summer into October. The pear tree and shrub are a species of genus ''Pyrus'' , in the family Rosaceae, bearing the p ...

s, and other

pome In botany, a pome is a type of fruit produced by flowering plants in the subtribe Malinae of the family Rosaceae. Well-known pomes include the apple, pear, and quince. Etymology The word ''pome'' entered English in the late 14th century, and re ...

and

stone fruit In botany, a drupe (or stone fruit) is an indehiscent fruit in which an outer fleshy part (exocarp, or skin, and mesocarp, or flesh) surrounds a single shell (the ''pit'', ''stone'', or ''pyrena'') of hardened endocarp with a seed (''kernel'') ...

s. After the female has chosen a suitable host, she will build an egg chamber under the fruit skin to receive the egg. She then turns around and places the egg in the cavity. Next, she slices a curved slit underneath the egg cavity, leaving the egg in a flap of flesh and causing a crescent-shaped scar on the outside of the fruit. Without this curved slit, eggs are killed by pressure from the growth of the host fruit.

Appearance

Plum curculio larvae are typically 6 to 9 mm long when fully grown, when they reach the

pupa A pupa ( la, pupa, "doll"; plural: ''pupae'') is the life stage of some insects undergoing transformation between immature and mature stages. Insects that go through a pupal stage are holometabolous: they go through four distinct stages in their ...

l stage measuring about 5 to 7 mm; all adult characteristics are visible in this stage prior to transformation. Adult plum curculio are about 4 to 6 mm long and have a small, rough snout colored with black, gray, and brown specks. Four pairs of ridges cover the

wings A wing is a type of fin that produces lift while moving through air or some other fluid. Accordingly, wings have streamlined cross-sections that are subject to aerodynamic forces and act as airfoils. A wing's aerodynamic efficiency is expresse ...

; however, because of the middle humps they appear to have only two ridges.

Hosts

The plum curculio can be found in apple,

nectarine The peach (''Prunus persica'') is a deciduous tree first domesticated and cultivated in Zhejiang province of Eastern China. It bears edible juicy fruits with various characteristics, most called peaches and others (the glossy-skinned, non-fuz ...

, plum,

cherry A cherry is the fruit of many plants of the genus ''Prunus'', and is a fleshy drupe (stone fruit). Commercial cherries are obtained from cultivars of several species, such as the sweet ''Prunus avium'' and the sour ''Prunus cerasus''. The nam ...

, peach,

apricot An apricot (, ) is a fruit, or the tree that bears the fruit, of several species in the genus ''Prunus''. Usually, an apricot is from the species '' P. armeniaca'', but the fruits of the other species in ''Prunus'' sect. ''Armeniaca'' are also ...

, pear and

quince The quince (; ''Cydonia oblonga'') is the sole member of the genus ''Cydonia'' in the Malinae subtribe (which also contains apples and pears, among other fruits) of the Rosaceae family (biology), family. It is a deciduous tree that bears hard ...

. It may also survive on wild plum,

hawthorn Hawthorn or Hawthorns may refer to: Plants * '' Crataegus'' (hawthorn), a large genus of shrubs and trees in the family Rosaceae * ''Rhaphiolepis'' (hawthorn), a genus of about 15 species of evergreen shrubs and small trees in the family Rosace ...

, and

crabapple ''Malus'' ( or ) is a genus of about 30–55 species of small deciduous trees or shrubs in the family Rosaceae, including the domesticated orchard apple, crab apples, wild apples, and rainberries. The genus is native plant, native to the temper ...

. It is found most commonly in areas east of the Rocky Mountains and in eastern

. The beetles are most active during the spring time when the weather is warm, damp, and cloudy. They are often seen in heavy leafed trees.

Injury or damage to fruit

Plum curculio beetles can cause irreparable damage to a fruit harvest. In badly damaged fruit, one can identify large scars and bumps due to feeding. Most internally damaged fruit (through burrowing into the fruit) drops prematurely.

Control

Control of the plum curculio is fairly easy to maintain. Application of proper insecticide during the pink and petal-fall stages of apples, also the petal-fall and shuck-split stages in peaches and cherries is usually enough to reduce plum curculio damage to a minimum. An important preventative measure is destroying the fallen, damaged host fruits before the adults emerge. Pest management at petal fall is also of particular importance.

References

External links

*
Pest Management Laboratory MSU - plum curculio
* ttps://www.canr.msu.edu/ipm/diseases/plum_curculio Michigan State University Extension fact sheet - plum curculiobr> University of Kentucky Entomology - plum curculio

Bugguide.net. Species ''Conotrachelus nenuphar'' - Plum Curculio
Molytinae Beetles of North America Agricultural pest insects Beetles described in 1797 {{agri-stub